Gastrin

Reference Intervals

Dogs: <28 ng/L

Cats: <40 ng/L

Please note that even short-term administration of proton pump inhibitors leads to dramatic increases in serum gastrin concentrations.

Sample Requirements & Shipping Information

• 0.3 mL of serum; fasting 8 to 12 hours is recommended.
• Gastrin is not stable at room temperature. Fasting serum should be collected and separated from the clot as soon as possible into a plastic tube for shipment. The serum must be frozen immediately.
• We recommend that after freezing, the serum be shipped using dry ice rather than only ice packs because at refrigerator temperatures gastrin is only stable for about 4 hours.

Turnaround

2-3 business days after receipt of samples.

General Information

Gastrin is an important gastrointestinal neuropeptide that is closely related to cholecystokinin and serves as one of the major stimuli of gastric acid secretion. The diagnostic utility of measurement of serum gastrin concentrations for the diagnosis of gastrinoma in dogs and cats was initially studied in the 1980’s. Gastrinomas are neuroendocrine tumors, usually located in the pancreas, that lead to increased production and secretion of gastric acid and in turn can cause gastric and duodenal ulcers leading to chronic vomiting, weight loss, and other clinical signs of chronic upper GI disease.

Interpretation

The GI Lab has analytically validated the Siemens IMMULITE 2000 assay for gastrin for use in dogs and cats. The reference intervals for serum gastrin concentration in dogs and cats using this assay were established as <28 ng/L and <40 ng/L, respectively. The assay serves as a diagnostic tool for dogs and cats with chronic vomiting that are suspected of having a gastrinoma. Until a more precise cut-off value for the diagnosis of a gastrinoma can be determined, we would recommend using the traditional cut-off value of 10 times the upper limit of the reference interval, or >280 ng/L for dogs and 400 ng/L for cats.

This cut-off value (10 times the upper limit of the reference interval), borrowed from human medicine, is likely rather conservative in dogs and cats and reflects a high prevalence of chronic atrophic gastritis in humans, which can cause severely elevated serum gastrin concentrations. In dogs, differential causes of elevated serum gastrin concentrations are chronic kidney disease, gastric outlet obstruction, small intestinal resection, immunoproliferative enteropathy of Basenji dogs, gastric dilatation-volvulus, and administration of proton pump inhibitors. All these differential diagnoses are considerably easier to rule out than atrophic gastropathy in humans. In cats, the only reports of increased serum gastrin concentrations in patients without a gastrinoma are in cats that have been treated with a proton pump inhibitor. Therefore, a less than 10-fold elevation of serum gastrin concentration may be sufficient to diagnose a gastrinoma if other differential diagnoses have been carefully ruled out.

Further reading

1. Dossin, O, Jones K, Ridgway M, Clark-Price S, Steiner JM, Suchodolski JS. Effect of omeprazole on serum gastrin concentrations and calcium metabolism in healthy dogs. Journal of Veterinary Internal Medicine 2011;25:688 (abstract).
2. Gould E, Clements C, Reed A, Giori L, Steiner J, Lidbury J, Suchodolski J, Brand M, Moyers T, Emery L, and Tolbert M. A prospective, placebo‐controlled pilot evaluation of the effect of omeprazole on serum calcium, magnesium, cobalamin, gastrin concentrations, and bone in cats. Journal of Veterinary Internal Medicine 2016;30,779-786.
3. Grady K, Ernst E, Secoura PL, Price J, Birkenheuer A, Vaden SL, Lidbury J, Gould E, Steiner JM, Tolbert MK. Gastric pH and serum gastrin concentration in age-matched healthy dogs and dogs with chronic kidney disease. Journal of Veterinary Internal Medicine 2023;37:2119-2124.
4. Ruhnke I, Suchodolski JS, Schwierk VM, Steiner JM. Analytical validation of a commercially available immunoassay for serum gastrin concentration in cats. Journal of Veterinary Internal Medicine 2010;24:753 (abstract).
5. Steiner JM, Ward C. Neuroendocrine tumors of the gastrointestinal tract. Small Animal Gastroenterology. Heilmann RM, Lidbury JA, Steiner JM (eds.), Schlütersche Verlagsanstalt, Hannover, Germany, 557-573, 2024.
6. Steiner JM, Findley KM, Suchodolski JS. Analytical validation of a commercial immunoassay for the measurement of serum gastrin concentrations in dogs. Journal of Veterinary Internal Medicine 2007;21:1438 (abstract).
7. Tolbert MK, Olin S, MacLane S, Gould E, Steiner JM, Vaden S, Price J. Evaluation of gastric pH and serum gastrin concentrations in cats with chronic kidney disease. Journal of Veterinary Internal Medicine 2017;31,1414-1419.