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Introduction ⬇

Trypsinogen is aproteolytic enzyme produced by the pancreas and released into the small intestine during normal digestion, where it is converted to trypsin. Chymotrypsin is also a proteolytic enzyme produced by the pancreas that helps break down proteins during digestion. Measurements of trypsin and chymotrypsin are useful in evaluating pancreatic function. Inadequate secretion can lead to malabsorption and abdominal discomfort.

Procedural Alert

This test is not reliable in older children and adults

Normal Findings ⬆ ⬇

Trypsin: 20–950 U/g or 20–950 μg/g stool

Chymotrypsin: 74–1200 μg/g or 74–1200 mg/kg stool

Procedure ⬆ ⬇

  1. Collect random stools specimens following the procedure for Collection and Transport of Random Specimens. Three separate, fresh stools are usually collected. Observe standard precautions.

  2. Ensure that the specimen is taken to the laboratory and tested within 2 hours.

  3. Give a cathartic (laxative) before obtaining a specimen from older children (saline or Fleet only).

Clinical Implications ⬆ ⬇

Decreased amounts of trypsin occur in the following conditions:

  1. Pancreatic deficiency syndromes (0–33 U/g or 0–33 μg/g stool)

  2. Cystic fibrosis (sweat chloride test is diagnostic) ( less than 20 U/g or less than 20 μg/g stool)

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain purpose of test, procedure for stool collection, and interfering factors.

  2. Advise the patient to avoid barium procedures and laxatives for 1 week before stool collection. Tell the patient to withhold pancreatic enzymes (if taking) for 5 days before providing a stool sample.

  3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal findings; explain the possible need for follow-up testing (e.g., sweat testing) and treatment (enzymes).

  2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert

  1. Diagnosis of pancreatic insufficiency should not be made until three specimens exhibit no 
trypsin activity.

  2. Bacterial protease may produce positive reactions when no trypsin is present; therefore, both positive and negative reactions should be carefully interpreted.

Interfering Factors ⬆

  1. No trypsin activity is detectable in constipated stools owing to prolonged exposure to intestinal bacteria, which inactivates trypsin.

  2. Barium and laxatives used less than 1 week before test affect results.

  3. In adults and older children, the test is unreliable owing to trypsin inactivation by intestinal flora.

  4. Bacterial proteases may produce positive reactions when no trypsin is present.