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Definition

Trypsin and chymotrypsin are substances released from the pancreas during normal digestion. When the pancreas does not produce enough trypsin and chymotrypsin, smaller-than-normal amounts can be seen in a stool sample.

This article discusses the test to measure trypsin and chymotrypsin in stool.

How the Test is Performed

There are several ways to collect the samples. Your health care provider will tell you how to collect the stool.

You can catch the stool on plastic wrap that is loosely placed over the toilet bowl and held in place by the toilet seat. Then put the sample in a clean container. One type of test kit contains a special tissue that you use to collect the sample. Then you put the sample in a clean container.

To collect a sample from infants and young children:

• If the child wears a diaper, line the diaper with plastic wrap.
• Place the plastic wrap so that urine and stool do not mix.

A drop of stool is placed on a thin layer of special gelatin. If trypsin or chymotrypsin are present, the gelatin will clear.

How to Prepare for the Test

Your provider will provide you with the supplies needed to collect the stool.

Why the Test is Performed

These tests are simple ways of finding out whether you have a decrease in pancreas function. This is most often due to chronic pancreatitis.

These tests are most often done in young children who are thought to have cystic fibrosis.

Note: This test is used as a screening tool for cystic fibrosis, but it does not diagnose cystic fibrosis. Other tests are needed to confirm a diagnosis of cystic fibrosis.

Normal Results

The result is normal if there is a normal amount of trypsin or chymotrypsin in the stool.

What Abnormal Results Mean

An abnormal result means the trypsin or chymotrypsin levels in your stool are below the normal range. This may mean that your pancreas is not working properly. Other tests may be done to confirm that there is a problem with your pancreas.

References

Forsmark CE. Chronic pancreatitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 59.

Liddle RA. Regulation of pancreatic secretion. In: Said HM, ed. Physiology of the Gastrointestinal Tract. 6th ed. San Diego, CA: Elsevier; 2018:chap 40.

Siddiqi HA, Rabinowitz S, Axiotis CA. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 23.