Gastrin

Gastrin is a hormone produced by G-cells in the lining of the stomach and the upper small intestine (duodenum). It plays an essential role in digestion by stimulating the stomach to release gastric acid, which helps break down food. Normally, gastrin levels rise after eating and usually return toward baseline as digestion progresses. However, abnormally high gastrin levels may indicate conditions such as Zollinger–Ellison syndrome (caused by gastrin-secreting tumors called gastrinomas), chronic atrophic gastritis, or pernicious anemia. Low gastrin levels are less commonly a major clinical concern but may be seen in situations associated with reduced stomach acid production or damage to the stomach lining.

The Gastrin test may be recommended if a person has symptoms such as recurrent or severe peptic ulcers, abdominal pain, chronic diarrhea, acid reflux, or unexplained weight loss. It is often ordered when a doctor suspects abnormal gastrin production or disorders related to excess stomach acid, such as gastrinoma, Zollinger–Ellison (ZE) syndrome, or G-cell hyperplasia. The test can also support the evaluation of pernicious anemia, where autoimmune damage to acid-secreting stomach cells leads to low acid levels and a compensatory rise in gastrin. In some cases, a stimulation test (such as a secretin test) may be performed to help confirm ZE syndrome. Additionally, the test may be ordered in selected cases for people with chronic gastritis, repeated ulcers, or those on long-term acid-suppressing medications (such as PPIs or H2 blockers), as these drugs can affect gastrin levels and require careful interpretation.

For this test, overnight fasting (8–12 hours) is required. Avoid eating or drinking anything except water before the test. It is also recommended to discontinue proton pump inhibitors (PPIs) at least 2 weeks before sample collection, but only after consulting the treating physician. This helps ensure accurate results.

Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Do not self-medicate and always consult a doctor to understand the test results correctly. 

Please note: This is an outsourced test. The sample for this test is collected by TATA 1MG and processed at a NABL accredited partnered lab.