Test DIRECTORY

Explore our comprehensive menu of laboratory tests designed to support accurate, reliable results across every specialty.

APG LAB's test directory provides a comprehensive list of specialty and general laboratory testing services.

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
There are currently 18 names in this directory beginning with the letter G.
Gabapentin, Serum or Plasma
Synonyms Neurontin® Expected Turnaround Time 2 - 5 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Documents Sample Report Specimen Requirements Specimen Serum or plasma Volume 1 mL Minimum Volume 0.3 mL Container Red-top tube, lavender-top (EDTA) tube, or green-top (heparin) tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant. Collection Transfer separated serum or plasma to a plastic transport tube. Storage Instructions Maintain specimen at room temperature. Stability Requirements Temperature Period Room temperature 14 days Refrigerated 14 days Frozen 14 days Freeze/thaw cycles Stable x3 Causes for Rejection Gel-barrier tube Test Details Limitations This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration. Methodology Liquid chromatography/tandem mass spectrometry (LC/MS-MS) Reference Interval 4.0−16.0 μg/mL Additional Information Gabapentin (Neurontin®) is an oral antiepileptic agent that is structurally related to the neurotransmitter γ-aminobutyric acid (GABA) but it does not interact with GABA receptors in the brain. Its mechanism of action is unknown but it has properties in common with other anticonvulsant medications. Gabapentin is only 3% bound to circulating protein in the blood and is not appreciably metabolized. Gabapentin is cleared by the kidneys and has an elimination half-life of five to seven hours.1 Steady-state concentrations are reached after one to two days with the time between ingestion and maximal serum concentration being two to three hours.2 For therapeutic drug monitoring, specimens should be drawn as trough levels. There are no significant drug interactions with other anticonvulsants. Adverse reactions are not common and are confined to somnolence (1.2%), ataxia (0.8%), fatigue (0.6%), nausea or vomiting (0.6%), and dizziness (0.6%).
Gastrin
Special Instructions This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample. Expected Turnaround Time 2 - 4 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Multiple-specimen Testing Pancreatic Polypeptide Related Documents Sample Report Specimen Requirements Specimen Serum, frozen Volume 0.5 mL Minimum Volume 0.3 mL (Note: This volume does not allow for repeat testing.) Container Red-top tube or gel-barrier tube Collection Separate serum from cells. Transfer the serum into a LabCorp PP transpak frozen purple tube with screw cap (LabCorp N° 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested. Storage Instructions Freeze immediately. Stability Requirements Temperature Period Frozen 14 days Freeze/thaw cycles Stable x3 Patient Preparation The patient must be fasting overnight, 12 to 14 hours. Causes for Rejection Gross hemolysis; patient not fasting; specimen not received frozen; gross lipemia; plasma specimen Test Details Use Diagnose Zollinger-Ellison (Z-E) syndrome; diagnose gastrinoma. Gastrin >1000 pg/mL with gastric acid hypersecretion (basal acid secretion >15 mmol/hour in a patient with peptic ulcer who has not had surgery) establishes unequivocally the diagnosis of the Zollinger-Ellison syndrome.4 Antral G-cell hyperplasia may relate to high gastrin levels and duodenal ulcer. Limitations Gastric hyperacidity must be documented. Gastric ulcer, chronic renal failure, hyperparathyroidism, pyloric obstruction, carcinoma of stomach,5 vagotomy without gastric resection, retained gastric antrum and short bowel syndrome have been reported with moderate elevations of gastrin levels. Gastrin levels are increased with pernicious anemia. H2-receptor blockers (cimetidine) may result in elevated levels. Overlap of serum gastrin values between gastrinoma and other states occurs. Up to 40% of Z-E patients have fasting gastrin values between 100 and 500 pg/mL, while a few patients with gastric or duodenal ulcer without gastrinoma, have results in this range. At least half of patients with the Z-E syndrome lack diagnostic serum gastrin levels, although in nearly all, fasting serum gastrin levels are increased.4 One report describes a patient with Z-E syndrome with a normal initial gastrin level.6 Methodology Immunochemiluminometric assay (ICMA) Reference Interval Pediatric1-3 and adults: • 0 to 1 month: 69−190 pg/mL • 2 to 22 months: 55−186 pg/mL • 22 months to 16 years: − Fasting 3 to 4 hours: 2−168 pg/mL − Fasting 5 to 6 hours: 3−117 pg/mL − Fasting >8 hours: 1−125 pg/mL • Older than 16 years: 0−115 pg/mL Additional Information Gastrin is secreted by antral G cells and stimulates gastric acid production, antral motility, and secretion of pepsin and intrinsic factor. The principle forms of gastrin in blood are G-34 (big gastrin, half-life is five minutes) and G-14 (minigastrin, half-life is five minutes). Each of these polypeptides circulates in nonsulfated (I) or sulfated (II) forms. Instilling acid into the stomach normally inhibits gastrin secretion. Elevated gastrin levels should be interpreted in light of gastric acid secretion and other parameters. The neuroendocrine tumors associated with the Zollinger-Ellison syndrome are characterized by elevated rates of gastric HCl secretion and upper gastrointestinal ulcer disease. Gastrin levels >500-600 pg/mL in a patient with basal acid hypersecretion often indicate gastrinoma, but antral G-cell hyperplasia cases can have gastrin levels >500 pg/mL and hyperchlorhydria. If gastrinoma is likely but fasting gastrin level is not diagnostic, the secretin test is the provocative test of choice. Absolute increase in serum gastrin level above the basal figure is preferred to percent change.4 I.V. secretin normally diminishes gastrin, but serum gastrin increases in gastrinoma patients. Wolfe provides an explanation for this paradoxical effect.4 Calcium infusion also stimulates gastrin release but does not distinguish other causes of ulcer as well as the secretin test. Protocols for stimulation tests are published.7 Fifteen percent to 26% of Z-E patients have evidence of Werner syndrome (multiple endocrine neoplasia type 1). It may include hyperparathyroidism, islet cell tumors of the pancreas, pituitary tumors, Cushing syndrome (adrenal glands), and hyperparathyroidism.8 Gastrinoma are malignant in 62% of cases, and 44% of patients have metastases. No consistent relationship has been established between Helicobacter pylori (Campylobacter pylori) and gastric acid secretion or serum gastrin levels. Features of gastrinoma additional to those of peptic ulcer may include diarrhea and steatorrhea. Gastrinomas are usually found in the pancreas but they may be primary in the duodenum. A few cases in which a gastrinoma was primary in the stomach have been reported. The morphology is that of foregut carcinoids.9
Gastrointestinal Profile, Stool, PCR
Synonyms Stool NAAT Stool PCR Test Includes Adenovirus F 40/41; astrovirus; Campylobacter; Clostridium difficile toxin A/B; Cryptosporidium; Cyclospora cayetanensis; E coli O157; Entamoeba histolytica; enteroaggregative E coli (EAEC); enteropathogenic E coli (EPAC); enterotoxigenic E coli (ETEC) lt/st; Giardia lamblia; norovirus GI/GII; Plesiomonas shigelloides; rotavirus A; Salmonella; Sapovirus; Shiga-like toxin-producing E coli (STEC) stx1/stx2; Shigella/enteroinvasive E coli (EIEC); Vibrio; Vibrio cholerae; Yersinia enterocolitica Special Instructions Introduce stool into orange Para-Pak® vial in small amounts such that level does not exceed fill-line on label. Cap securely and shake vial to distribute sample into the Cary-Blair preservative. Expected Turnaround Time 2 - 3 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Ova and Parasites Examination Stool Culture Related Documents For more information, please view the literature below. Gastrointestinal Profile (BioFire) Flyer Sample Report Specimen Requirements Specimen Stool placed in a stool culture transport vial (Para-Pak® C&S orange) Volume Add stool until level in Para-Pak® vial is at fill-line on vial label. Do not over fill. Container Para-Pak® orange or sterile container with Cary-Blair preservative liquid medium Collection If possible, allow patient to urinate before collecting stool specimen so as to avoid contaminating the stool specimen with urine. Catch the stool specimen in a clean, empty wide-mouthed container or place plastic wrap over the opening of the toilet bowl to prevent the stool specimen from falling into the bowl. Do not mix urine or water with the stool specimen. For diaper collected specimens, line the diaper with plastic wrap. Do not submit the diaper. Place small amounts of the stool specimen into the orange-labeled Para-Pak® vial using the spoon affixed to the Para-Pak® vial cap, taking care not to let the volume in the vial exceed the RED fill-line indicated on the vial label. Cap the Para-Pak® vial and shake the vial 10 times to ensure complete distribution of the stool into the preservative. The stool specimen must be placed into the Para-Pak® vial within one hour of the stools production for optimum results. Label the Para-Pak® vial with the patient's name, date of birth, date of collection and time of collection. Be sure the Para-Pak® vial cap is securely in place and that the vial is not leaking. Storage Instructions Refrigerate. Room temperature storage and transport up to four days is acceptable. Causes for Rejection Specimen not received in Cary-Blair preservative medium; specimen vial leaking; specimen >96 hours since collection; frozen specimen; rectal swab; specimen below fill line on container (underfilled) Test Details Use Gastrointestinal disease can be caused by many agents, including bacteria, viruses and parasites. Culture for bacteria will not pick up the viruses or parasites. Tests for parasites will not detect the viruses or the bacteria. This GI profile is a multiplexed nucleic acid test intended for the simultaneous qualitative detection and identification of nucleic acids from multiple bacteria, viruses and parasites directly from stool samples in Cary-Blair transport media obtained from individuals with signs and/or symptoms of gastrointestinal infection. Limitations The performance of this test has not been established for patients without signs and symptoms of gastrointestinal illness. Virus, bacteria and parasite nucleic acid may persist in vivo independently of organism viability. Additionally, some organisms may be carried asymptomatically. Detection of organism targets does not imply that the corresponding organisms are infectious or are the causative agents for clinical symptoms. The detection of organism nucleic acid is dependent upon proper sample collection, handling, transportation, storage and preparation. Failure to observe proper procedures in any one of these steps can lead to incorrect results. There is a risk of false-positive and false-negative results caused by improperly collected, transported or and handled specimens. Methodology Polymerase chain reaction (PCR)
Gastrointestinal Stromal Tumors (GISTs), c-KIT Mutation Analysis
Synonyms Tyrosine Kinase Inhibitor (TKI, Imatinib) Responsiveness Special Instructions This test is not New York State approved. Expected Turnaround Time 10 - 14 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Gastrointestinal Stromal Tumors (GISTs), PDGFRA Mutation Analysis Specimen Requirements Specimen Formalin-fixed, paraffin-embedded (FFPE) tissue or five unstained slides from a paraffin block in 10-μM sections and a matching H&E reference slide Volume Formalin-fixed, paraffin-embedded (FFPE) block or five unstained slides from paraffin block in 10-μM sections and a matching H&E reference slide Minimum Volume 2 mm x 2 mm tumor area with ≥50% tumor Container Slides or blocks Collection Please provide a copy of the pathology report. Please direct any questions regarding this test to oncology customer service at 800-345-4363. Storage Instructions Maintain blocks and slides at room temperature. Causes for Rejection Tumor block containing insufficient tumor tissue or tumor fixed in a heavy metal fixative; broken or stained slides Test Details Use c-KIT is a proto-oncogene that encodes a type III transmembrane tyrosine kinase. c-KIT and its ligand stem cell factor have a key role in survival, proliferation, differentiation, and functional activation of cells. Limitations Genomic DNA is purified from the specimen provided. Exons 9, 11, 13, and 17 of c-KIT gene coding are subjected to PCR amplification and bidirectional sequencing in duplicate to identify sequence variations. This assay has a sensitivity to detect approximately 10% of cells containing the c-KIT mutations in a background of nonmutant cells. This assay will not detect the mutation below the sensitivity of this assay. This test was developed, and its performance characteristics determined, by LabCorp. It has not been cleared or approved by the US Food and Drug Administration (FDA). The FDA has determined that such clearance or approval is not necessary. Methodology Polymerase chain reaction (PCR) and DNA sequencing Additional Information Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal tract, located mostly in the stomach (60%) and small intestine (35%). Approximately 80% of GISTs have a mutation in c-KIT and 5% to 10% of GISTs have a mutation in PDGFRA. PDGFRA mutations are mutually exclusive with c-KIT mutations but activate similar signal transduction pathways that support GIST oncogenesis. The location of c-KIT and PDGFRA mutations in GISTs is associated with the site of origin, histological phenotype, and treatment response to tyrosine kinase inhibitors (TKI, such as imatinib and sunitinib). Patients with mutations in c-KIT exon 11 have been shown to have significantly better response rates to imatinib treatment when compared with patients who have the c-KIT exon 9 mutations or no mutation. Patients with mutations in c-KIT exon 9 may benefit from dose escalation depending on tolerance. Secondary mutations usually occur in c-KIT kinase domains in patients after imatinib treatment resulting in resistance to this drug. Most known mutations in the PDGFRA gene are associated with imatinib response with the exception of D842V mutation. In a subset of intestinal high-risk GISTs lacking c-KIT/PDGFRA mutations, 7% have a mutation in BRAF. Kinase inhibitors targeting BRAF may be effective therapeutic options in this molecular GIST subset.
Gaucher Disease, DNA Analysis
Special Instructions If cultured cells are needed, anadditional 7-12 days may be required. Additional culture fee may be included. Expected Turnaround Time 9 - 15 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Specimen Requirements Specimen Whole blood, amniotic fluid, chorionic villus sample (CVS) (submission of maternal blood is required for fetal testing), or LabCorp buccal swab kit (buccal swab collection kit contains instructions for use of a buccal swab) Volume 7 mL whole blood, 10 mL amniotic fluid, 20 mg CVS, or LabCorp buccal swab kit Minimum Volume 3 mL whole blood, 5 mL amniotic fluid, 10 mg CVS, or two buccal swabs Container Lavender-top (EDTA) tube, yellow-top (ACD) tube, sterile plastic conical tube or two confluent T25 flasks for fetal testing, or LabCorp buccal swab kit Storage Instructions Maintain specimen at room temperature. Causes for Rejection Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; one buccal swab; wet buccal swab Test Details Use This assay will detect carriers of Gaucher disease in the Ashkenazi Jewish population. Enzyme testing is the preferred test to detect affected individuals. DNA testing may be used to confirm affected status. Limitations To determine affected status, biochemical testing is recommended. This assay detects ∼95% of the mutations responsible for Gaucher disease type I and 50% to 60% of types II and III (childhood and juvenile onset) in the Ashkenazi Jewish population. Seventy-five percent of mutations in non-Jewish Caucasians are also detected. The frequency of the various glucocerebrosidase mutations can vary significantly between different ethnic groups. Since this analysis does not detect all mutations, results must be combined with clinical information for the most accurate interpretation. This test is not appropriate for determining affected status for childhood/juvenile onset disease. Methodology Polymerase chain reaction (PCR); primer extension; flow-sorted bead array analysis for eight mutations in the glucocerebrosidase gene. The mutations tested include: N370S (A1226G), L444P (C1448T), D409H (G5957C), V395L (5912T), 84GG (G-GG), IVS2+1 (insA), R496H (G1604A), and 55 bp deletion (C1263del). Additional Information Gaucher disease (OMIM 230800) is an autosomal recessive disorder caused by a decrease in the levels of the enzyme glucocerebrosidase. Decreased levels of glucocerebrosidase can result in visceral changes, such as organomegaly and thrombocytopenia, and skeletal changes, such as bone lesions. There are three subtypes of Gaucher disease. Type 1 is the most common subtype. Individuals affected with type 1 may have onset of symptoms in adolescence, though some remain asymptomatic well into adulthood. Type 1 is effectively treated through enzyme replacement therapy.
Gene Sequencing, aHUS
Specimen Requirements Specimen Whole blood; acceptable alternate: cheek swab (buccal swab) Volume 3 mL Minimum Volume 1 mL Container Lavender- top (EDTA) tube Collection Invert tube 4 times to ensure adequate mixing. Storage Instructions Room temperature Stability Requirements Temperature Period Room temperature 1 month Causes for Rejection Sample contamination Test Details Use The exonic regions of 20 genes are sequenced and analyzed as part of this panel, including ADAMTS13, C2, C3, C3AR1, CD46(MCP), CFB, CFD, CFH, CFHR1, CFHR2, CFHR3, CFHR4, CFHR5, CFI, DGKE, MASP2, MMACHC, THBD, PLG, WT1 and C5 p.Arg885. The sequences have been compared to the reference Human genome (Hg18) sequence. Methodology Next Generation Sequencing (NGS)
Genital Culture, Routine
Synonyms Culture, Genital, Routine Test Includes Culture; isolation, identification (additional charges/CPT code[s] may apply), and if culture results warrant, susceptibility testing (at an additional charge). CPT coding for microbiology and virology procedures often cannot be determined before the culture is performed. Requests with only a written order and no test number indicated will be processed according to Default Testing for Routine Microbiology. Special Instructions Specify specimen source and pertinent clinical information on the request form. Specimens from other sources, such as genital, stool, urine, upper and lower respiratory specimens, cannot be cultured under the aerobic bacterial culture test number. If specimens are incorrectly submitted with an order for aerobic bacterial culture, the laboratory will process the specimen for the test based on the source listed on the request form. The client will not be telephoned to approve this change, but the change will be indicated on the report. Check expiration date of transport; do not use expired devices. Expected Turnaround Time 3 - 5 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information GC (Neisseria gonorrhoeae) Culture Only Group B Streptococcus Colonization Detection, NAA Group B Streptococcus Colonization Detection, NAA With Reflex to Susceptibilities Routine Microbiology Related Documents Sample Report Specimen Requirements Specimen Swab of vagina, cervix, discharge, aspirated endocervical, endometrial, prostatic fluid, or urethral discharge. Use swab to inoculate Jembec for transport to the laboratory and recovery of Neisseria gonorrhoeae; swab should also be sent in transport device. Volume One swab and one inoculated Jembec; or one swab Container Bacterial culture transport swab with gel and Jembec Collection Female: Do not use lubricant on speculum. Cervical mucus should be removed first before inserting swab into endocervical canal, move swab from side to side allowing several seconds for absorption of organisms by the swab. Return swab to the transport tube and label. Male: Using small wire swab, gently scrape the anterior urethral mucosa or, use a swab to collect specimen of urethral discharge. Storage Instructions Maintain specimen swab and Jembec at room temperature. Do not refrigerate. Causes for Rejection Inappropriate specimen transport device; unlabeled specimen or name discrepancy between specimen and request label; specimen received after prolonged delay (usually more than 72 hours); specimen received in expired transport Test Details Use Isolate and identify potentially aerobic pathogenic organisms, including Gardnerella vaginalis and Neisseria gonorrhoeae; establish the diagnosis of gonorrhea in medicolegal cases. Limitations Does not include Trichomonas vaginalis, Chlamydia trachomatis, Ureaplasma urealyticum, Mobiluncus sp, or yeast speciation. For antepartum screening at 35 to 37 weeks of gestation for maternal Group B Streptococcus colonization, use Group B Streptococcus Colonization Detection, NAA [188132] or Group B Streptococcus Colonization Detection, NAA With Reflex to Susceptibilities [188139]. Methodology Culture
Gestational Diabetes Screen (ACOG Recommendations)
Synonyms Glucose Tolerance, Gestational Diabetes (One-hour) Test Includes 50-gram one-hour glucose tolerance challenge Special Instructions The patient need not be fasting. The one-hour screen requires a 50-gram oral glucose load followed by a plasma glucose determination one hour later. (Refer to Additional Information below.) See the online Endocrine Appendix: Glucose Tolerance: Gestational Diabetes Mellitus for further information regarding glucose tolerance testing. Expected Turnaround Time Within 1 day Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Glucose Tolerance: Gestational Diabetes Mellitus Related Documents Sample Report Specimen Requirements Specimen Serum or plasma Volume 1 mL serum or plasma each tube Minimum Volume 0.5 mL serum or plasma each tube Container Gel-barrier tube or gray-top (sodium fluoride/potassium oxalate plasma) tube Collection Note: A fasting blood sample is not required. Draw one hour specimen after a 50-gram glucose challenge. The patient should remain seated and not smoke throughout the test. Submit 1 mL serum or plasma for one-hour specimen. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label tube with patient's name and collection time interval (ie, one-hour). Storage Instructions Maintain specimen at room temperature.1 Stability Requirements Temperature Period Room temperature 14 days Refrigerated 14 days Frozen 14 days Freeze/thaw cycles Stable x3 Patient Preparation None; glucose challenge is administered without regard to time of day or time of last meal. Causes for Rejection Frozen gray-top tube (frozen plasma from gray-top is acceptable); stressed patient (surgery, infection, corticosteroids) should not have GTT; specimen not labeled with collection time intervals (i.e., one hour) Test Details Use Screening test for gestational diabetes Methodology Enzymatic Contraindications Patient with known history of diabetes mellitus Reference Interval 65−139 mg/dL Critical Value 500 mg/dL Additional Information The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women be screened for gestational diabetes mellitus (GDM)—whether by patient history, clinical risk factors, or with a 50-gram, one-hour loading test at 24 to 28 weeks of gestation to determine blood glucose levels—and suggests relying on the result of the 100-gram, three-hour oral glucose tolerance test for diagnosis (often referred to as a "two-step" method).2 The American Diabetes Association (ADA)3 released standards that vary from the ACOG recommendations. The ADA recommends a simplified "one-step" approach to the screen and diagnosis of gestational diabetes mellitus with a 75-gram, two-hour glucose tolerance test. The LabCorp test according to the ADA recommendations is Gestational Glucose Tolerance Screening and Diagnostics Test (Two-hour, ADA Recommendations) [101000]. A glucose tolerance screen glucose threshold >139 mg/dL after a 50-gram load identifies approximately 80% of women with gestational diabetes mellitus, while the sensitivity is further increased to approximately 90% by a threshold >129 mg/dL. Perform a diagnostic 100-gram oral glucose tolerance test (102004) on a separate day on women who exceed the chosen threshold on 50-gram screening.
Glucagon, Plasma
Synonyms Pancreatic Glucagon Special Instructions Contact the LabCorp supply department for collection kit. Expected Turnaround Time 5 - 10 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Pancreatic Polypeptide Related Documents Sample Report Specimen Requirements Specimen Plasma with Trasylol®, frozen Volume 1 mL Minimum Volume 0.5 mL (Note: This volume does not allow for repeat testing.) Container Lavender-top (EDTA) tube (chilled) Collection Trasylol® kits may be ordered through the PeopleSoft system (LabCorp N° 33328). Using a chilled 6-mL lavender-top (EDTA) tube taken from the kit, collect a whole blood specimen. Mix the specimen several times by inverting the EDTA collection tube. After removing the cap from the EDTA draw tube, take one of the sterile, Beral pipettes (from under the gray foam), and add 0.25 mL Trasylol® to the EDTA tube. Recap the EDTA tube and invert several times to mix well. Centrifuge the EDTA tube to separate the plasma from the cells, and immediately transfer the plasma into one of the brown screw-cap transfer tubes provided in the kit. There should be a "Trasylol® Added" label affixed to the brown transfer tubes. Cap and freeze the labeled transfer tube containing the EDTA plasma with Trasylol® added. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested. Storage Instructions Freeze. Stability Requirements Temperature Period Room temperature Unstable Refrigerated Unstable Frozen 7 days Freeze/thaw cycles Stable x1 Patient Preparation Overnight fasting for basal levels. No isotopes administered 24 hours prior to venipuncture. Patient should not be in a stress state at time of drawing. If diabetic, patient should be in good control before specimen is drawn. Causes for Rejection Sample not collected with Trasylol®; sample not submitted in tube with Trasylol label, gross hemolysis; recently administered radioisotopes; specimen not received frozen; serum, sodium citrate, or heparinized plasma specimen; lipemia Test Details Use For use (1) when considering a glucagon-secreting tumor of the pancreas, (2) in the diagnosis and management of diabetes mellitus and other carbohydrate metabolism disorders, and (3) in the diagnosis of glucagon deficiency in patients with hypoglycemia. Limitations The Millipore glucagon RIA kit employed by LabCorp has been shown to exhibit a small cross-reactivity with oxyntomodulin and glicentin.1 Results of this test are labeled for research purposes only by the assay's manufacturer. The performance characteristics of this assay have not been established by the manufacturer. The result should not be used for treatment or for diagnostic purposes without confirmation of the diagnosis by another medically established diagnostic product or procedure. The performance characteristics were determined by LabCorp. Methodology Radioimmunoassay (RIA) Reference Interval 50−150 pg/mL Additional Information Glucagon is produced by the alpha cells of the islets of Langerhans of the pancreas in response to a decrease in plasma glucose concentrations and in response to increased concentrations of specific amino acids.2 The glucagon precursor protein undergoes tissue-specific post-translation processing.2 Glucagon secretion is controlled by a number of factors. In nondiabetic individuals, secretion is stimulated by protein-rich meals, but inhibited by carbohydrate-rich meals. Hypoglycemia activates the autonomic nervous system which stimulates glucagon release into the portal circulation.3-5 Glucagon release is also regulated in a paracine manner by insulin, zinc and other factors secreted from neighboring β- and δ-cells within the islet of Langerhans.5 In healthy individuals, glucagon released is inhibited by hyperglycemia, mixed nutrient meals, and oral intravenously administered amino acids. Glucagon is a counter-regulatory hormone opposing the actions of insulin in glucose homoeostasis. The intravenous administration of glucagon raises blood glucose substantially in nondiabetic individuals.6 Glucagon is thought to play an important role in the maintenance of fasting and postprandial glucose homeostasis.6,7 By stimulating hepatic glucose output, glucagon counterbalances the action of insulin and serves to maintain circulating glucose and prevent insulin mediated hypoglycemia.2,5 Blockade of endogenous glucagon secretion with somatostatin causes glucose concentrations to decrease.6 A highly specific glucagon receptor is abundantly expressed on hepatocytes.6 Glucagon binding to this receptor leads to increased hepatic glucose production, fatty acid oxidation and ketogenesis.6,7 Glucagon stimulates glycogenolysis and gluconeogenesis, changing the liver from an organ of glucose release.2,3 Glucagon secretion inhibits gastric emptying, increases gastric output, increases bile flow and increases cardiac muscle contraction. Glucagon also has lipolytic effects.2 Insulin treatment of diabetic patients can cause acute hypoglycemia which is often exacerbated by a deficient glucagon response.3,4,6,8,9 The exact pathophysiologic mechanisms for this dysregulation is not fully defined but has been attributed, in part, to a lack of intra-islet insulin effect.5,10 Alternatively, some patients with controlled type 1 diabetes experience inappropriately elevated plasma glucagon levels in the context of hyperglycemia.6 Both type 1 and type 2 diabetes frequently exhibit an inappropriately high glucagon response to a meal.10 The high levels of glucagon have been shown to contribute importantly to diabetic hyperglycemia and can result in ketoacidosis.3-7,11 Relative hyperglucagonemia, in the setting of deficient insulin secretion may contribute to the development of fasting and postprandial hyperglycemia in the patients.6-8 Increased plasma glucagon levels have been demonstrated in many forms of physiological stress that are not typically associated with hypoglycemia.9 Hyperglucagonemia has been documented in patients with trauma, burns, surgery, sepsis, hemorrhage, acute myocardial infarction, cardiac arrest and neonatal hypoxia.9 A glucagonoma is a rare tumor of the alpha cells of the pancreas that results in up to a 1000-fold overproduction of glucagon.12,13 Serum glucagon concentrations in excess of 500 pg/mL are strongly suggestive of glucagonoma.12 These tumors are associated with glucagonoma syndrome. The raised glucagon concentrations produce hyperglycemia, diabetes mellitus and glucose intolerance. Excessive glucagon action produces a catabolic state resulting in weight loss.2,14 Glucagonomas frequently present with a specific dermatitis referred to as necrolytic migratory erythema (NME).15 Patients with NME develop erythematous blisters and swelling in areas subject to greater friction and pressure, including the lower abdomen, buttocks, perineum, and groin.1,13 In addition, these patients are prone to deep venous thrombosis that may be a significant cause of death. Other common symptoms of glucagonoma include depression,diarrhea and anemia.2,12,14 Because the symptoms of early disease are nonspecific, patients often present at a later stage with extensive metastatic disease.2
Glucose
Synonyms Blood Sugar Expected Turnaround Time Within 1 day Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Documents Sample Report Specimen Requirements Specimen Serum Volume 1 mL Minimum Volume 0.5 mL Container Red-top tube or gel-barrier tube Collection Separate serum from cells within 45 minutes of collection. Label specimen as serum. Storage Instructions Maintain specimen at room temperature. Stability Requirements Temperature Period Room temperature 14 days Refrigerated 14 days Frozen 14 days Freeze/thaw cycles Stable x3 Patient Preparation Patient should fast for 12 hours. Causes for Rejection Gross hemolysis; patient not fasting; blood stored overnight on clot; improper labeling Test Details Use Diagnose diabetes mellitus; evaluate disorders of carbohydrate metabolism including alcoholism; evaluate acidosis and ketoacidosis; evaluate dehydration, coma, hypoglycemia of insulinoma, neuroglycopenia. A fasting glucose ≥125 mg/dL on more than one occasion is adequate for the diagnosis of diabetes mellitus. An OGTT is not necessary in this setting. Infants, especially with tremor, cyanosis, convulsions, and respiratory distress should have stat glucose, particularly if there is maternal diabetes, postmaturity, asphyxia, hemolytic disease of the newborn, or possible sepsis. Babies too large or small for gestational age should also have glucose in the first 24 hours of life. Random blood sugars can be used to monitor therapy in diabetics or evaluate presence of insulinoma.1,2 Limitations Mild glucose impairment can exist with fasting glucose within the normal range. Measurement of plasma glucose without spinal fluid glucose can miss neuroglycopenia. To the extent that innovative new methods deviate from reference methods, such alternative techniques may be unreliable for certain patient care needs.3 Fingerstick glucose determination in shock are lower than venous glucose and are dangerously misleading.4 Methodology Enzymatic Reference Interval 65−99 mg/dL Additional Information Recent evidence revealed a diurnal variation in FPG, with mean FPG higher in the morning than in the afternoon, indicating that many cases of undiagnosed diabetes would be missed in patients seen in the afternoon. Glucose concentrations decrease ex vivo with time in whole blood because of glycolysis. The rate of glycolysis, reported to average 5% to 7% [~0.6 mmol/L (10 mg/dL)] per hour, varies with the glucose concentration, temperature, white blood cell count, and other factors. Glycolysis can be attenuated by inhibition of enolase with sodium fluoride (2.5 mg fluoride/mL of blood) or, less commonly, lithium iodoacetate (0.5 mg/mL of blood). These reagents can be used alone or, more commonly, with anticoagulants such as potassium oxalate, EDTA, citrate, or lithium heparin. Although fluoride maintains long-term glucose stability, the rate of decline of glucose in the first hour after sample collection in tubes with and without fluoride is virtually identical. (Note that leukocytosis will increase glycolysis even in the presence of fluoride if the white cell count is very high). After four hours, the glucose concentration is stable in whole blood for 72 hours at room temperature in the presence of fluoride. In separated, nonhemolyzed, sterile serum without fluoride, the glucose concentration is stable for fourteen days at 25°C and 4°C. Glucose can be measured in whole blood, serum, or plasma, but plasma is recommended for diagnosis. The molality of glucose (ie, amount of glucose per unit water mass) in whole blood and plasma is identical. Although red blood cells are essentially freely permeable to glucose (glucose is taken up by facilitated transport), the concentration of water (kg/L) in plasma is ~11% higher than that of whole blood. Therefore, glucose concentrations in plasma are ~11% higher than whole blood if the hematocrit is normal. Glucose concentrations in heparinized plasma are reported to be 5% lower than in serum. The reasons for the latter difference are not apparent but may be attributable to the shift in fluid from erythrocytes to plasma caused by anticoagulants. The glucose concentrations during an OGTT in capillary blood are significantly higher than those in venous blood [mean of 1.7 mmol/L (30 mg/dL), equivalent to 20% to 25%], but the mean difference in fasting samples is only 0.1 mmol/L (2 mg/dL). Although methods for glucose analysis exhibit low imprecision at the diagnostic decision limits of 7.0 mmol/L [(126 mg/dL), fasting] and 11.1 mmol/L [(200 mg/dL), postglucose load], the relatively large intraindividual biological variability (CVs of ~5% to 7%) may produce classification errors. On the basis of biological variation, glucose analysis should have analytical imprecision <3.4%, bias <2.6%, and total error 125 mg/dL, a two-hour postprandial glucose >200 mg/dL is virtually diagnostic of diabetes mellitus and obviates the need for a glucose tolerance test. An oral glucose tolerance test (OGTT) is not necessary in the setting of sufficiently high fasting and two-hour postprandial results. Other causes of high glucose (serum or plasma) include nonfasting specimen; recent or current IV infusions of glucose; stress states such as myocardial infarct,5 brain damage, CVA,6 convulsive episodes, trauma, general anesthesia; Cushing disease; acromegaly; pheochromocytoma; glucagonoma; severe liver disease; pancreatitis; drugs (thiazide and other diuretics, corticoids, many others are reported to affect glucose). The danger of hypoglycemia (low glucose) is lack of a steady supply of glucose to the brain (neuroglycopenia). Causes of low glucose: Excess insulin, including rare insulin autoimmune hypoglycemia, surreptitious insulin injection, and sulfonylurea use; glycolysis in specimens overheated or old; serum permitted to stand on clot in red-top tube for chemistry profile. Very prompt removal of plasma and analysis is needed in cases of marked leukocytosis. Hypoglycemia should be confirmed by specimens drawn in fluoride tubes (gray-top tubes). With hypoglycemia, symptoms must be correlated with plasma glucose. Three major groups of hypoglycemia are defined: reactive, fasting, and surreptitious. The reactive group includes alimentary hyperinsulinism, prediabetic, endocrine deficiency, and idiopathic functional groups.7 Postprandial hypoglycemia may occur after gastrointestinal surgery, and is described with hereditary fructose intolerance, galactosemia, and leucine sensitivity. • Pancreatic islet cell tumors (insulinomas) − cause hypoglycemia in fasting individuals or after exercise. Measurement of simultaneous glucose, C-peptide, and insulin levels at the time of spontaneous hypoglycemia help to differentiate insulinoma from other conditions. The glucose:insulin ratio is useful in the diagnosis of insulinoma: insulin levels inappropriately increased for plasma glucose. An intravenous tolbutamide test with plasma glucose and serum insulin determinations may be used for evaluation of insulin-secreting islet cell tumors. The test is positive in approximately 75% of patients with these tumors.7 Glucagon and leucine stimulation tests are less frequently utilized. • Extrapancreatic tumors−rare bulky fibromas, sarcomas, mesotheliomas, and carcinomas, including hepatoma and adrenal tumors • Adrenal insufficiency (Addison disease), including congenital adrenal hyperplasia • Hypopituitarism, isolated growth hormone or ACTH deficiency • Starvation, malabsorption−but starvation does not cause hypoglycemia in normal persons • Drugs including insulin (see above), oral hypoglycemic agents, and alcoholism, especially with starvation. Ethanolism is a common cause of hypoglycemia. Other drugs can depress glucose levels. • Liver damage, including fulminant hepatic necrosis (hepatitis, toxicity), and severe congestive failure • Tumor-induced hypoglycemia appears to be caused by increased production of an insulin-like substance (insulin-like growth factor II) by the tumor. This substance induces increased utilization of glucose by the peripheral tissues and the tumor, and impairs the counterregulatory effect of growth hormone by suppressing growth hormone secretion.8,9 Infancy and childhood: Infants with tremor, convulsions and/or respiratory distress should have stat glucose, particularly in the presence of maternal diabetes, hemolytic disease of the newborn (erythroblastosis fetalis); babies too large or small for gestational age should also have glucose level measured in the first 24 hours of life. A large number of entities relate to neonatal hypoglycemia, including glycogen storage diseases, galactosemia, hereditary fructose intolerance, ketotic hypoglycemia of infancy, fructose-1,6-diphosphatase deficiency, carnitine deficiency (a treatable disease presenting as Reye syndrome), and nesidioblastosis.
Glucose, Body Fluid
Special Instructions The request form must state site of fluid (ie, pleural, peritoneal, pericardial, synovial). Expected Turnaround Time 1 - 2 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Documents Sample Report Specimen Requirements Specimen Any fresh body fluid Volume 1 mL Minimum Volume 0.5 mL Container Sterile container Collection Collect aseptically into sterile tube. Storage Instructions Room temperature Stability Requirements Temperature Period Room temperature 14 days Refrigerated 14 days Frozen 14 days Freeze/thaw cycles Stable x3 Patient Preparation On synovial fluid collection only, patient should fast for eight hours. Causes for Rejection Improper labeling Test Details Use Decreased fluid glucose concentration is usually associated with septic or inflammatory processes; in pleural effusion, very low glucose is a facet of rheumatoid effusion: pleural fluid glucose <50 mg/dL characterizes rheumatoid effusion. It is often much less. Methodology Enzymatic Reference Interval • Peritoneal: Not established • Pleural: − Transudate: Equal to simultaneously drawn plasma − Exudate: Equal to simultaneously drawn plasma • Synovial: Equal to simultaneously drawn plasma The method performance specifications have not been established for this test in body fluid. The test result should be integrated into clinical context for interpretation. Additional Information Potts et al describe loculated effusions or empyemas with low glucose and low pH. Low glucose is found with empyema, tuberculosis, neoplasia, and rheumatoid effusion.1 In cases of malignant pleural effusions, when there is low pleural fluid glucose (<60 mg/dL) and pH <7.30, a probability of 90% that the cytologic yield will be positive was reported.2
Gluten
Expected Turnaround Time 3 - 4 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Individual Allergens Related Documents Sample Report Specimen Requirements Specimen Serum Volume 0.2 mL Container Red-top tube or gel-barrier tube Storage Instructions Room temperature Stability Requirements Temperature Period Room temperature 14 days Refrigerated 14 days Frozen 3 months Freeze/thaw cycles Stable x3 Test Details Methodology Thermo Fisher ImmunoCAP®
Gluten Sensitivity Antibodies Cascade
Synonyms Nonceliac Gluten Sensitivity Test Includes IgA and IgG antibodies to deamidated gliadin peptide and tissue transglutaminase (tTG/DGP screen), IgG antibodies to gliadin (AGA), wheat allergen-specific IgE (wheat IgE). Profile starts with tTG/DGP screen test. If positive, testing stops. If negative, testing reflexes to the AGA test. If positive, testing stops. If negative, it reflexes to the wheat IgE test. Expected Turnaround Time 3 - 6 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Documents For more information, please view the literature below. Celiac Disease Testing Services LABupdate: Gluten Sensitivity Testing Sample Report Specimen Requirements Specimen Serum Volume 1 mL Minimum Volume 0.5 mL (Note: This volume does not allow for repeat testing.) Container Red-top tube or gel-barrier tube Storage Instructions Room temperature Stability Requirements Temperature Period Room temperature 14 days Refrigerated 14 days Frozen 14 days Causes for Rejection Lipemia; hemolysis; microbially-contaminated sera Test Details Use This profile is recommended for children and adults with suspected sensitivity to gluten. Limitations Patients with gluten sensitivity who are on a gluten-free diet may have negative serological test results for gluten sensitivity. Methodology Enzyme-linked immunosorbent assay (ELISA): tTG/DGP screen and AGA; quantitative allergen-specific IgE: wheat IgE Additional Information Gluten is a protein found in wheat, rye, and barley. Gliadin is the alcohol-soluble fraction of gluten that contains the bulk of the toxic components of gluten. It is resistant to degradation in the human upper gastrointestinal tract and is able to pass through the epithelial barrier of the intestine. Gluten sensitivity is a state of heightened immunological responsiveness to ingested gluten. It represents the spectrum of diseases with diverse manifestations such as enteropathy (celiac disease), dermatopathy (dermatitis herpetiformis), neurological disorders (ataxia and neuropathy), and may be underlying reason for many other nonspecific symptoms like anemia, chronic fatigue, joint inflammation and pain, migraines, depression, attention-deficit disorder, epilepsy, osteoporosis and osteopenia, infertility, recurrent fetal loss, vitamin deficiencies, short stature, failure to thrive, delayed puberty, dental enamel defects, and autoimmune disorders. Patients with gluten sensitivity are reported to have increased mortality and its prevalence in the general population is up to 12%. Antibodies to deamidated gliadin peptide and tissue transglutaminase are specific to celiac disease while antibodies to native gliadin are present in patients with and without gastrointestinal manifestations and are serological evidence of gluten sensitivity. Another subset of patients may have gluten sensitivity expressed in the form of allergic reaction to foods containing gluten like wheat. All of those patient groups may benefit from gluten-free diet. This screening profile is designed to aid in the diagnosis of different forms of gluten sensitivity. Step One: The screening starts with testing for IgA and IgG antibodies to deamidated gliadin peptide (DGP) and tissue transglutaminase (tTG) that allows for simultaneous detection for all four types of antibodies in one test (tTG/DGP screen). This step will aid in the diagnosis of gluten-sensitive enteropathies including celiac disease. Antibodies to DGP and tTG are highly specific and sensitive for those conditions.1,2 When the result is positive, testing stops and the interpretive comment on the report would read: "Suggestive of celiac disease or other gluten-sensitive enteropathies. Subsequent testing for Endomysial Antibody, IgA [164996] and/or genetic testing for Celiac Disease HLA DQ Association [167082] may be indicated for further patient evaluation." When result is negative, testing will reflex to the second step. Step Two: In the second step, the test for IgG antibodies to native gliadin (AGA) is performed. AGA currently remain the most sensitive markers of the whole spectrum of gluten sensitivity including all the extraintestinal manifestations.1,3 When the result is positive, testing stops and the interpretive comment would read: "Suggestive of nonceliac gluten sensitivity. The patient may benefit from a gluten-free diet." When the result is negative, testing will reflex to the third step. Step Three: In the third and last step, the test for wheat allergen-specific IgE is performed. Allergic reaction to wheat may mimic the clinical presentation of gluten sensitivity like celiac disease and is one of the common food allergies in children. The triggering agent, however, may not be just gluten but any other protein or combination of proteins found in wheat.4 Because wheat allergy patients may also be allergic to other grains with similar proteins like rye and barley,4 they will benefit from the gluten-free diet. When the result is positive, testing stops and the interpretive comment would read: "Suggestive of wheat allergy. The patient may benefit from a gluten-free diet." When the result is negative, testing stops and the interpretive comment would read: “Not suggestive of gluten sensitivity.”
Group B Streptococcus Colonization Detection, NAA
CPT: 87081; 87150. If susceptibilities are performed, an additional charge will be added (87184). Include LOINC® in print Expected Turnaround Time 1 - 2 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Documents Sample Report Specimen Requirements Specimen Swab of vaginal and rectal specimen Volume Single or double bacterial swab in Amies agar gel transport or equivalent (non-nutritive transport medium) Minimum Volume Single bacterial swab in Amies agar gel transport or equivalent (non-nutritive transport medium) Collection Collection of both a vaginal and rectal swab specimen is strongly recommended. Swab the lower vagina (vaginal introitus), followed by the rectum (ie, insert swab through the anal sphincter) using the same swab. Move swab from side to side, or rotate the swab at the collection site, allowing several seconds for absorption of organisms by the swab. Cervical, perianal, perirectal, or perineal specimens are not acceptable, and a speculum should not be used for culture collection. Storage Instructions Specimen is stable for 24 hours at room temperature. If arrival at lab will extend beyond 24 hours, then refrigerate. Causes for Rejection Inappropriate specimen transport; use of ESwab™; inappropriate transport conditions; improper labeling; specimen received after 24 hours and not refrigerated; cervical/endocervical, perianal, perirectal or perineal specimen, or any source other than vagina and rectum Test Details Use Antepartum detection of group B β-hemolytic streptococci. Limitations A positive result does not necessarily indicate the presence of viable organisms. Patients who have used systemic or topical (vaginal) antibiotic treatment in the week prior, as well as patients diagnosed with placenta previa, should not be tested using this assay. Methodology Selective broth enrichment culture and real-time PCR Additional Information In the US, group B Streptococcus (GBS) remains a leading cause of early-onset neonatal sepsis. The most common mode of acquisition by the neonate is exposure to the maternal genital flora in utero through ruptured membranes or by contamination during passage through the birth canal. Infection is manifested in two major forms, early-onset septicemic infection manifest in the first few days of life and late-onset meningitis that occurs during the first few months of life. The Centers for Disease Control and Prevention (CDC) and the American Congress of Obstetricians and Gynecologists (ACOG) practice guidelines recommend universal antepartum screening at 35 to 37 weeks of gestation. These guidelines specify co-collection of a vaginal and rectal swab specimen to maximize sensitivity of GBS detection. Per the CDC and ACOG, swabbing both the lower vagina and rectum substantially increases the yield of detection compared with sampling the vagina alone. Rates of maternal colonization have not changed, but universal antepartum screening along with the use of intrapartum antibiotic prophylaxis has resulted in a decrease of early-onset GBS disease. In November 2010, the CDC published revised guidelines recommending that, in addition to culture, antepartum vaginal/rectal specimens could be tested using a nucleic acid amplification (NAA) test following incubation in a selective enrichment broth medium to enhance the detection of GBS. Susceptibility testing is not routinely performed, as this organism is universally susceptible to penicillin, and surveillance for resistance is not recommended. The CDC and the ACOG recommend reflex susceptibility testing to clindamycin and erythromycin (D-zone test to detect inducible clindamycin resistance) for group B Streptococcus only for those patients at high risk for anaphylactic shock due to penicillin allergy. For those patients without likely evidence of severe anaphylaxis, the CDC and ACOG recommend the use of cefazolin as the agent of choice for intrapartum chemoprophylaxis without the need for susceptibility testing. For those patients with GBS that is resistant to clindamycin, treatment with vancomycin is recommended without the need for additional susceptibility testing. Even though it is tested together with clindamycin in the D-zone test, erythromycin is no longer an acceptable alternative for intrapartum GBS prophylaxis for penicillin-allergic women at high risk for anaphylaxis, and susceptibility results for this agent will not be reported.
Growth Hormone
Synonyms Human Growth Hormone (hGH) Special Instructions This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample. Expected Turnaround Time 2 - 4 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Growth Hormone Stimulation Growth Hormone Suppression Test for Acromegaly Multiple-specimen Testing Related Documents Sample Report Specimen Requirements Specimen Serum Volume 0.8 mL Minimum Volume 0.3 mL (Note: This volume does not allow for repeat testing.) Container Red-top tube or gel-barrier tube Collection If a red-top tube is used, transfer separated serum to a plastic transport tube. Label tube with time of collection and patient's name. Storage Instructions Refrigerate Stability Requirements Temperature Period Room temperature 7 days Refrigerated 14 days Frozen 14 days Freeze/thaw cycles Stable x3 Patient Preparation Random growth hormone sampling should be performed on fasting patients who have rested for at least 30 minutes prior to collection. Growth hormone stimulation and suppression protocols are described in the online Endocrine Appendices: Growth Hormone Stimulation and Growth Hormone Suppression. Causes for Rejection Gross hemolysis; lipemia; plasma specimen Test Details Use Pituitary function test useful in the diagnosis of hypothalamic disorder, hypopituitarism, acromegaly, and ectopic growth hormone production by neoplasm Limitations A single fasting growth hormone (GH) level is of limited value. Secretion of GH is episodic and pulsatile. GH has a half-life of 20 to 25 minutes. Testing for growth hormone deficiency or excess is best done as part of a dynamic test involving specific stimuli (see the online Endocrine Appendices: Growth Hormone Stimulation and Growth Hormone Suppression). Insulin-like growth factor-1 can also be useful in assessing growth hormone status. As in the case of any diagnostic procedure, results must be interpreted in conjunction with the patient's clinical presentation and other information available to the physician. Methodology Immunochemiluminometric assay (ICMA) Reference Interval 0.0−10.0 ng/mL Additional Information Human growth hormone (hGH) is a polypeptide hormone secreted from the acidophil cells of the anterior pituitary gland. Secretion is episodic and is associated with exercise, the onset of deep sleep or postprandially in response to falling glucose levels. Synthesis and release are under the control of hypothalamic releasing peptides and inhibitory peptides such as somatostatin. More recently, a gastric peptide, ghrelin, has been shown to also stimulate HGH secretion. The mediator of many hGH actions in the periphery, insulin-like growth-factor I (IGF-I) exerts an inhibitory effect through negative feedback mechanisms.1 hGH in circulation consists of several molecular isoforms, with 22,000 Dalton hGH being the most abundant, followed by a 20,000 Dalton hGH variant produced by alternative splicing. Approximately 50% of circulating hGH is bound to a high affinity binding protein.2 hGH is physiologically important in two main areas. Firstly, it has an integral role in skeletal growth which is well demonstrated in either excess or deficiency in childhood. The action of hGH in part is mediated through IGF-I as well as promoting protein synthesis and the uptake of amino acids into cells. Secondly, hGH influences intermediary metabolism by stimulating lipolysis and is antagonistic to the insulin-mediated uptake of glucose.3 hGH secretion is stimulated by hypoglycemia and suppressed by hyperglycemia. In childhood, symptoms of hGH deficiency are retarded growth and dwarfism. Etiology is often unknown and an absolute or relative deficiency usually becomes apparent at about two years of age. Diagnosis can be confirmed by demonstrating low serum hGH which does not respond to stimulation tests. hGH deficiency is a major cause of severe short stature and diagnosis at an early stage is essential for successful therapy.4 Hyposecretion in adults usually becomes apparent during the laboratory investigation of hypopituitarism.5,6 Hypersecretion, commonly due to adenoma of the acidophil cells, is characterized by two conditions depending on whether it becomes apparent before or after fusion of the bony epiphyses. In childhood, excess hGH is characterized by gigantism. Heights of eight feet may be achieved and may also be associated with hypogonadism. In adults, acromegaly results, a condition characterized by progressive thickening of bone and soft tissue. Diagnosis is usually confirmed by dynamic function testing, which demonstrates a raised serum hGH level that does not fall in response to an oral glucose load.7 In conditions where there are nutritional disturbances, such as anorexia, starvation, renal failure, and hepatic cirrhosis, increased basal hGH levels may be found. Recombinant hGH is available for treatment of hGH deficiency in both children and adults.4-6 hGH excess is treated by surgery, irradiation therapy, or somatostatin analogues.8,9 More recently, pegvisomant, a hGH receptor antagonist, which shares structural homology to hGH and competes with hGH for binding to the hGH receptor, has been developed.10 The IDS iSYS hGH assay conforms to the recommendations outlined in the recently published consensus statement on the standardization and evaluation of growth hormone assays.11 The assay is calibrated to the WHO International Standard for Somatropin from NIBSC, code 98/574.12 The assay is 100% specific for the 22 kDalton form of hGH and has no cross-reactivity with pegvisomant.13
Growth Hormone, Two Specimens
Special Instructions This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample. Expected Turnaround Time 2 - 6 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Gynecologic Pap Test (Image-guided), Liquid-based Preparation and Human Papillomavirus (HPV) High-risk DNA Detection
Test Includes Image-guided liquid-based cytology evaluation and evaluation for the presence of high-risk HPV DNA sequences Special Instructions Include date of birth, Social Security number (or other identification number), previous malignancy, drug therapy, radiation therapy, last menstrual period (LMP), postmenopausal patient (PMP), surgery (including surgical biopsies), exogenous hormones, abnormal vaginal bleeding, abnormal Pap results, IUD, and all other pertinent clinical information on the cytology test request form. Note: In accordance with criteria established by CLIA, Pap tests will be referred for pathologist review if laboratory personnel suspect: • Reactive or reparative cellular changes • Atypical squamous or glandular cells of undetermined significance • Cells in the premalignant or malignant category In these cases, LabCorp will charge for the associated service. (Slides that are routinely reviewed by a pathologist for quality control purposes are not included.) If ThinPrep® vials are QNS for the hybrid capture assay, then a test requiring a lower input volume will be automatically performed if there is sufficient volume to perform that assay. Expected Turnaround Time 2 - 5 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Cervical / Vaginal Specimens Related Documents For more information, please view the literature below. When Is a Double Negative a Positive Outcome? Specimen Requirements Specimen Cervical cells collected by one of the methods described below. Volume ThinPrep® vial or SurePath™ vial Minimum Volume A minimum volume cannot be determined for the ThinPrep® vial, because it varies depending on the cellularity of the specimen. The entire SurePath™ specimen should arrive intact. Container ThinPrep® vial or SurePath™ vial Collection ThinPrep® Vial−Broom Only: Broom-like collection technique: Obtain a sample from the cervix using a broom-like device by inserting the brush portion into the cervical os and then rotate the brush five times. Rinse the collection device in the PreservCyt® solution by pushing the brush into the bottom of the vial 10 times, forcing the bristles to bend apart to release the cervical material. As a final step, twirl the brush between the thumb and forefinger vigorously to release additional cellular material. Discard the collection device. Tighten the cap on the ThinPrep® vial so that the torque line on the cap passes the torque line on the vial. SurePath™ Vial: When using the SurePath™ vial, the cervical broom must be used for specimen collection. Insert the broom into the cervical os and rotate five times. Place the broom head into the CytoRich™ preservative fluid in the SurePath™ collection vial. Tightly cap the vial. Storage Instructions Maintain liquid-based cytology specimens at room temperature. Pap processing must be done within 21 days of collection. Specimens in ThinPrep® vials must be processed for testing within three months of collection for HPV. SurePath™ vial must be processed for testing within 21 days of collection for HPV. Patient Preparation Patient should avoid douches 48 to 72 hours prior to examination. Specimen should not be collected during or shortly after menstrual period. Causes for Rejection Improper collection; inadequate specimen; improper labeling; specimen leaked in transit; quantity not sufficient for analysis; name discrepancies; specimen submitted on male patient; specimen submitted in vial that expired according to manufacturer's label; frozen specimen. For Pap: liquid-based cytology specimen more than 21 days old. For HPV: specimen more than three months old in ThinPrep® vial; specimen more than 21 days old in SurePath™ vial Test Details Use Diagnose primary or metastatic neoplasm. The high-risk HPV test is used for types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68 without differentiation of the individual type. This assay aids in the diagnosis of sexually-transmitted HPV infection and in the triage of patients with an ASCUS Pap test result. Limitations Failure to obtain adequate ectocervical, endocervical, or vaginal cell population is suboptimal for evaluation. Excessive use of lubricating jelly on the vaginal speculum will interfere with cytologic examination and may lead to unsatisfactory Pap results. The use of the liquid-based cytology specimen for multiple tests may limit the volume available for Pap reprocessing or HPV testing. A negative result does not exclude the possibility of an HPV infection since very low levels of infection or sampling error may produce a false-negative result. This test detects only the 13 most common high-risk HPV types and cannot determine the specific HPV type present. Methodology Image-guided liquid-based Pap test; nucleic acid amplification (NAA)
Gynecologic Pap Test, Liquid-based Preparation
Special Instructions Include date of birth, Social Security number (or other identification number), previous malignancy, drug therapy, radiation therapy, last menstrual period (LMP), postmenopausal patient (PMP), surgery (including surgical biopsies), exogenous hormones, abnormal vaginal bleeding, abnormal Pap results, IUD, and all other pertinent clinical information on the cytology test request form. Note: In accordance with criteria established by CLIA, Pap tests will be referred for pathologist review if laboratory personnel suspect: • Reactive or reparative cellular changes • Atypical squamous or glandular cells of undetermined significance • Cells in the premalignant or malignant category In these cases, LabCorp will charge for the associated service. (Slides that are routinely reviewed by a pathologist for quality control purposes are not included.) Expected Turnaround Time 2 - 6 days Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary. Related Information Cervical / Vaginal Specimens Specimen Requirements Specimen Vial with PreservCyt® solution, ThinPrep®; SurePath® vial with CytoRich™ fixative Collection When using the ThinPrep® method, a gynecologic specimen is collected using a brush and plastic spatula as a cervical sampling system. Insert the brush into the endocervical canal until only the bottommost fibers are exposed. Slowly rotate the brush 1/4 to 1/2 turn in one direction. Do not over-rotate the brush. Then, rotate the brush in the PreservCyt® solution 10 times while pushing against the wall of the ThinPrep® vial. Swirl the brush vigorously to release additional material. Discard the brush. Obtain an adequate sample from the ectocervix using a plastic spatula. Swirl the spatula vigorously in the PreservCyt® vial 10 times, and discard the spatula. Tighten the cap on the ThinPrep® PreservCyt® solution container so that the torque line on the cap passes the torque line on the vial. When using the TriPath SurePath™ method, the cervix (broom) or the endocervical brush/plastic spatula combination collection device(s) must be used with the broom/brush being inserted into the cervical os and rotated five times. Once collected, the removable head(s) of the collection device(s) is dropped into the CytoRich™ preservative fluid in the TriPath SurePath™ collection vial. Also, the cervix brush and Wallach brush may be used in obtaining a ThinPrep® specimen, but the brush is rinsed vigorously in the vial and discarded; the brush head is not placed in the ThinPrep® PreservCyt® vial. Record the patient's name and ID number on the vial, and place it and the test request form in a specimen bag for transport to the laboratory. Storage Instructions Maintain specimen at room temperature. Specimen must be processed for testing within 21 days of collection. Patient Preparation Patient should avoid douches 48 to 72 hours prior to examination. Specimen should not be collected during or shortly after menstrual period. Excessive use of lubricating jelly on the vaginal speculum will interfere with cytologic examination. Causes for Rejection Improperly labeled vial; specimen more than 21 days old (from collection date) in liquid-based preservative; specimen submitted in vial that expired according to manufacturer's label; frozen specimen Test Details Limitations Failure to obtain adequate ectocervical, endocervical, or vaginal cell population is suboptimal for evaluation. Excessive use of lubricating jelly on the vaginal speculum will interfere with cytologic examination and may lead to unsatisfactory Pap results. Methodology ThinPrep® Pap test system; TriPath SurePath® Pap test

Common Lab Tests

Complete Blood Count

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This test, also known as a CBC, is the most common blood test performed. It measures the types and numbers of cells in the blood, including red and white blood cells and platelets. This test is used to determine general health status, screen for disorders and evaluate nutritional status. It can help evaluate symptoms such as weakness, fatigue and bruising, and can help diagnose conditions such as anemia, leukemia, malaria and infection.

Prothrombin Time

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Also known as PT and Pro Time, this test measures how long it takes blood to clot. This coagulation test measures the presence and activity of five different blood clotting factors. This test can screen for bleeding abnormalities, and may also be used to monitor medication treatments that prevent the formation of blood clots.

Basic Metabolic Panel

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This test measures glucose, sodium, potassium, calcium, chloride, carbon dioxide, blood urea nitrogen and creatinine which can help determine blood sugar level, electrolyte and fluid balance as well as kidney function. The Basic Metabolic Panel can help your doctor monitor the effects of medications you are taking, such as high blood pressure medicines, can help diagnose certain conditions, or can be part of a routine health screening. You may need to fast for up to 12 hours before this test.

Lipid

Panel

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The lipid panel is a group of tests used to evaluate cardiac risk. It includes cholesterol and triglyceride levels.

Liver Panel

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The liver panel is a combination of tests used to assess liver function and establish the possible presence of liver tumors.

Hemoglobin A1C

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This test is used to diagnose and monitor diabetes.

Urinalysis

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Often the first lab test performed, this is a general screening test used to check for early signs of disease. It may also be used to monitor diabetes or kidney disease.

Cultures

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Cultures are used to test for diagnosis and treatment of infections. Illnesses such as urinary tract infections, pneumonia, strep throat, MRSA and meningitis can be detected and tested for appropriate antibiotic treatment.

APG Labs offers fast & accurate results for a wide range of specialty tests!

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