Patient Test Information


Also known as:

Chymotrypsin, fecal

Formal name:

Stool Chymotrypsin

Related tests:

Immunoreactive Trypsinogen, Fecal Fat, Stool Elastase

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Why Get Tested?

To help detect and evaluate pancreatic insufficiency

When to Get Tested?

When you have symptoms such as persistent diarrhea; foul-smelling, bulky, greasy stools; malnutrition; malabsorption; and vitamin deficiency and pancreatic insufficiency is suspected

Sample Required?

A fresh stool sample, uncontaminated with urine

Test Preparation Needed?

If you are taking pancreatic enzymes, you may be instructed to discontinue taking the enzymes 5 days before providing the stool sample.

How is it used?

The chymotrypsin test is used along with other tests, such as a fecal fat and/or fecal elastase, to evaluate both children and adults for pancreatic insufficiency.

Pancreatic insufficiency is the inability of the pancreas to produce and/or transport enough digestive enzymes to break down food in the intestine and facilitate absorption of nutrients. It typically occurs as a result of progressive pancreatic damage.

When is it ordered?

A chymotrypsin test may be ordered when a person has signs and symptoms of pancreatic insufficiency, such as:

  • Persistent diarrhea
  • Abdominal cramps
  • Weight loss
  • Foul-smelling, bulky, greasy stools
  • malnutrition
  • malabsorption
  • Vitamin deficiency
  • In children, an inability to gain weight, delayed growth

What does the test result mean?

A positive result, indicating the presence of chymotrypsin in the stool, is normal. Chymotrypsin is present in the stool of healthy individuals.

A negative result may mean that the person tested has pancreatic insufficiency. It is not diagnostic, but it does indicate that further testing may be indicated.

Is there anything else I should know?

If someone's pancreas is not functioning properly, the individual will need to be monitored closely by the person's healthcare provider. The person may find symptom relief and nutritional improvement by taking prescribed oral enzymes and vitamin supplements.

What is being tested?

Chymotrypsin is an enzyme that digests protein in the small intestine. This test measures the amount of chymotrypsin in stool to help evaluate whether someone's pancreas is functioning properly.

Chymotrypsinogen, the inactive precursor of chymotrypsin, is produced in the pancreas and transported to the small intestine. In the small intestine, it is activated to form chymotrypsin. It is one of the enzymes responsible for breaking down the protein in food into smaller pieces, called peptides. Chymotrypsin is detectable in the stool if the pancreas is functioning normally.

Individuals with pancreatic dysfunction may either have blocked pancreatic ducts or the cells that produce chymotrypsinogen may be damaged or destroyed. Such cell damage and duct blockage cause pancreatic insufficiency because the amount of enzymes transported to the small intestine is inadequate for proper food digestion. This is often seen in conditions such as chronic pancreatitis and sometimes pancreatic cancer.

How is the sample collected for testing?

A fresh stool sample, uncontaminated with urine, is collected.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

If you are taking pancreatic enzymes, you may be instructed to discontinue taking the enzymes 5 days before providing the stool sample.

  1. What causes pancreatic insufficiency?

    Pancreatic insufficiency can be caused by recurrent acute pancreatitis or by chronic pancreatitis. It is less frequently but sometimes associated with pancreatic cancer. Other causes of insufficiency may include celiac disease, Crohn disease, autoimmune pancreatitis (immunoglobulin G4-related disease), Zollinger-Ellison syndrome, and some surgical procedures that can lead to a decrease in gastrointestinal or pancreatic function.

    Additionally, people who are carriers of a mutation in the CFTR gene may have pancreatic insufficiency and experience the associated signs and symptoms. (See the article on CFTR Gene Mutation Testing to learn more about carriers.)

    In children, it is most frequently associated with cystic fibrosis (CF) or Shwachman-Diamond Syndrome (SDS). SDS is the second most common cause of inherited pancreatic insufficiency, after CF. All those with SDS have some degree of pancreatic insufficiency beginning at infancy.

  2. What other laboratory tests might be done if I or my child has a negative cymotrypsin test?

    Your healthcare provider may order a stool test for Fecal Fat or fecal elastase or a blood test for amylase or lipase to look at other aspects of pancreas and digestive function. Read the article on Pancreatic insufficiency to learn more.