Gastrin

CPT: 82941 (per specimen)
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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

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

Patient Preparation

The patient must be fasting overnight, 12 to 14 hours.

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

Causes for Rejection

Gross hemolysis; patient not fasting; specimen not received frozen; gross lipemia; plasma specimen

Clinical Information

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.

Footnotes

1. Meites S, Buffone GJ, Cheng MH, et al, eds. Pediatric Clinical Chemistry, Reference (Normal) Values. 3rd ed. Washington, DC: AACC Press;1989:131.
2. Sann L, Chayvialle AP, Bremond A, Lambert R. Serum gastrin level in early childhood. Arch Dis Child. 1975 Oct; 50(10):782-785. 1244175
3. Janik JS, Akbar AM, Burrington JD, Burke G. Serum gastrin levels in infants and children. Pediatrics. 1977 Jul; 60(1):60-64. 876736
4. Wolfe MM. Diagnosis of gastrinoma: Much ado about nothing? Ann Intern Med. 1989 Nov 1; 111(9):697-699. 2802429
5. Rakic S, Milicevic MN. Serum gastrin level in patients with intestinal and diffuse type of gastric cancer. Br J Cancer. 1991 Dec; 64(6):1189. 1764387
6. Yanda RJ, Ostroff JW, Ashbaugh CD, Guis MS, Goldberg HI. Zollinger-Ellison syndrome in a patient with normal screening gastrin level. Dig Dis Sci. 1989 Dec; 34(12):1929-1932. 2598759
7. Malagelada JR, Glanzman SL, Go VL. Laboratory diagnosis of gastrinoma. II. A prospective study of gastrin challenge tests. Mayo Clin Proc. 1982 Apr; 57(4):219-226. 7040824
8. Jensen RT, Gardner JD, Raufman JP, Pandol SJ, Doppman JL, Collen MJ. Zollinger-Ellison syndrome: Current concepts and management. Ann Intern Med. 1983 Jan; 98(1):59-75 (review). 6336642
9. Wilander E. Endocrine cell tumours. In: Whitehead R, ed. Gastrointestinal and Oesophageal Pathology. New York, NY: Churchill Livingstone;1989: 629-641.

References

Cherner JA, Doppman JL, Norton JA, et al. Selective venous sampling for gastrin to localize gastrinomas. A prospective assessment. Ann Intern Med. 1986 Dec; 105(6):841-847. 3535602
Clain JE. Diagnosis and management of gastrinoma (Zollinger-Ellison syndrome). Mayo Clin Proc. 1982 Apr; 57(4):265-267. 7070121
den Hartog G, van der Meer JW, Jansen JB, van Furth R, Lamers CB. Decreased gastrin secretion in patients with late-onset hypogammaglobulinemia. N Engl J Med. 1988 Jun 16; 318(24):1563-1567. 3374528
Fraker DL, Norton JA. The role of surgery in the management of islet cell tumors. Gastroenterol Clin North Am. 1989 Dec; 18(4):805-830. 2559034
Friesen SR, Tomita T. Pseudo-Zollinger-Ellison syndrome: Hypergastrinemia, hyperchlorhydria without tumor. Ann Surg. 1981 Oct; 194(4):481-493. 7283508
Green DW, Gómez G, Greeley GH Jr. Gastrointestinal peptides. Gastroenterol Clin North Am. 1989 Dec; 18(4):695-733. 2693350
Malagelada JR, Davis CS, O'Fallon WM, Go VL. Laboratory diagnosis of gastrinoma. I. A prospective evaluation of gastric analysis and fasting serum gastrin levels. Mayo Clin Proc. 1982 Apr; 57(4):211-218. 7070117
McQuaid KR. Much ado about gastrin. J Clin Gastroenterol. 1991 Jun; 13(3):249-254. 1676713
Modlin IM, Jaffe BM, Sank A, Albert D. The early diagnosis of gastrinoma. Ann Surg. 1982 Nov; 196(5):512-517. 7125738
Solcia E, Capella C, Fiocca R, Cornaggia M, Bosi F. The gastroenteropancreatic endocrine system and related tumors. Gastroenterol Clin North Am. 1989 Dec; 18(4):671-693. 2575601
Warburton R, Close JR. The in vitro stability of gastrin in serum and whole blood. Ann Clin Biochem. 1987 May; 24(Pt 3):320-321. 3606018
Wolfe MM, Jain DK, Edgerton JR. Zollinger-Ellison syndrome associated with persistently normal fasting serum gastrin concentrations. Ann Intern Med. 1985 Aug; 103(2):215-217. 4014903

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
004390 Gastrin, Serum 2333-3 004392 Gastrin, Serum pg/mL 2333-3

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