What Is a Secretin Test?

A secretin test is a medical test where a doctor administers the hormone secretin and takes a sample from a tube positioned in the duodenum to determine how the pancreas, gallbladder, and stomach responded. This test uses a natural stimulating hormone found in the body in a specific challenge to assess endocrine function. A doctor may order this test if he believes a patient has an endocrine imbalance or another health condition that might cause abnormal results. It takes place in a hospital or clinic and can take an hour or more, depending on what other tests may be needed at the same time.

The first step in the secretin test is to take a baseline measurement. Then the patient receives secretin either intravenously or through a nasogastric tube. After a waiting period to let the hormone work, the care provider takes another sample. He can check for the presence of gastrin, a stomach hormone, or other hormones, and compare the before and after samples. Differences can highlight how the body handles secretin, and can determine if the patient has a medical problem.

In patients with a condition called Zollinger-Ellison Syndrome, for example, the secretin causes levels of gastrin to rise. The stimulation with secretin may also fail to trigger the right response in the pancreas or gallbladder. A lab will return results along with a normal range to use for reference, so the doctor can determine if the patient's response to the secretin test was unusual.

It may be given as part of the secretin-cholecystokinin test, which includes another test for gallbladder function. The secretin test can be part of the workup for a patient with suspected health issues. It can also be a follow-up after treatment for a medical condition. This can determine how well the patient responded to treatment, and if additional care is necessary. The results will also create a reference that may be useful in the future in the event of more testing.

This test is relatively low risk for the patient. It can cause some discomfort but does not involve the introduction of potential allergens or toxins. The biggest risk can be irritation around injection and blood draw sites, and an experienced caregiver can limit the chances of this problem. If a doctor recommends a secretin test, patients may want to ask why the test is recommended, what the possible results might be, and what kinds of treatment options may be available. Information may be limited until the doctor actually has test results to look at, but she can provide a general overview.