Nome formal
Stool trypsin and chymotrypsin
Este artigo foi revisto pela última vez em
Este artigo foi modificado pela última vez em
13 de Maio de 2018.
At a Glance
Why Get Tested?
To screen for cystic fibrosis and pancreatic insufficiency by evaluating pancreas function
When To Get Tested?
If you or your newborn or infant have symptoms of pancreatic insufficiency or cystic fibrosis such as persistent diarrhea, foul-smelling bulky greasy stools, malnutrition, and vitamin deficiency
Sample Required?
A fresh stool sample, uncontaminated with urine
What is being tested?
Trypsin and chymotrypsin are proteolytic enzymes. Their job is to digest protein in the small intestine. Normally, their precursors (their inactive forms: trypsinogen and chymotrypsinogen) are produced in the pancreas and transported to the small intestine. In the small intestine, trypsinogen is activated, turned into trypsin, by an enzyme in the intestinal mucosa and then trypsin in turn activates chymotrypsinogen to chymotrypsin. Together, they form powerful chemicals responsible for breaking down the protein in food into smaller pieces called peptides. Trypsin and chymotrypsin will be detectable in the small intestine and in the stool if the pancreas is functioning normally.

In people with cystic fibrosis, mucous plugs can block the pancreatic ducts that lead into the small intestine, preventing trypsinogen and chymotrypsinogen from reaching the intestine. Similarly, mucous plugs can block small airway passages in the lungs, making one susceptible to respiratory infections and chronic pulmonary disease. It is usually the respiratory complications of cystic fibrosis that eventually prove fatal for patients with this disease.

Individuals with pancreatic dysfunction (tissue damage or blockage) may either have blocked pancreatic ducts or the cells that produce trypsinogen and chymotrypsinogen may be damaged or destroyed. Such cell damage causes pancreatic insufficiency, in which enzyme transport to the small intestine is inadequate for proper food digestion. This is often seen in conditions such as chronic pancreatitis and pancreatic cancer.

How is the sample collected for testing?

A fresh stool sample is collected, uncontaminated with urine. For an infant, a urine collection bag with adhesive edges that can be stuck to the baby’s skin and a plastic-lined diaper are both used to keep urine out of the stool and to keep the stool from soaking into the diaper.

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

No test preparation is needed.
Accordion Title
Common Questions
View Sources
Sources Used in Current Review

(Update May 5, 2007) Lehrer, J. MedlinePlus Medical Encyclopedia. Trypsin and Chymotrypsin in Stool. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003594.htm. Accessed January 2009.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER, Bruns DE, eds. St. Louis: Elsevier Saunders; 2006, p 622-623.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. 1088-1091.

Cystic Fibrosis Foundation. Testing for Cystic Fibrosis. Available online at http://www.cff.org/AboutCF/Testing/ through http://www.cff.org. Accessed January 2009.

Cleveland Clinic. Cystic Fibrosis. Available online at http://my.clevelandclinic.org/disorders/cystic_fibrosis/hic_cystic_fibrosis.aspx# through http://my.clevelandclinic.org. Accessed January 2009.

Denise I. Quigley, PhD, FACMG. Co-Director Cytogenetics/Molecular Genetics, Airport Way Regional Laboratory, Portland, OR.

Peter Jacky, PhD, FACMG. Director of Cytogenetics and Molecular Genetics, Airport Way Regional Laboratory, Portland, OR.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

NIDDK (July 1997). Cystic Fibrosis Research Directions. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) [NIH Publication No. 97-4200]. Available online at http://www.niddk.nih.gov/health/endo/pubs/cystic/cystic.htm through http://www.niddk.nih.gov.

Cystic Fibrosis Foundation. Sweat Testing Procedure and Commonly Asked Questions. [On-line information]. Available online at http://www.cff.org/publications01.htm through http://www.cff.org.

Tait, J., et. al. (26 March 2001). Cystic Fibrosis. GENEReviews [On-line information]. Available online at http://www.genetests.org/.

Mayo Clinic (2001, February 09). What is Cystic Fibrosis? Mayo Clinic [On-line information]. Available online at http://www.mayoclinic.com/invoke.cfm?objectid=2CEBF76F-D36A-4D15-B937BFF91AB51438 through http://www.mayoclinic.com.

MEDLINEplus (2002, January 2, Updated). Cystic Fibrosis. MEDLINEplus Health Information [On-line Information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000107.htm.

MEDLINEplus (2002, January 2, Updated). Sweat Electrolytes. MEDLINEplus Health Information [On-line Information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003630.htm.

MEDLINEplus (2002, January 2, Updated). Trypsin and chymotrypsin in stool. MEDLINEplus Health Information [On-line Information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003594.htm.

Mountain States Genetics (1999, September, Revised). Cystic Fibrosis (CF). Newborn Screening Practitioner’s Manual [On-line information]. Available online at http://www.mostgene.org/pract/prac26.htm through http://www.mostgene.org.

National Institutes of Health (1995, November). Facts About Cystic Fibrosis. National Heart, Lung, and Blood Institute NIH Publication No. 95-3650 [On-line information]. Available online at http://www.nhlbi.nih.gov/health/public/lung/other/cf.htm through http://www.nhlbi.nih.gov.

Quest Diagnostics NEWS (2002, Winter). What is the Best Test to Screen for Cystic Fibrosis? [On-line serial]. PDF available for download at http://www.questdiagnostics.com/hcp/files/02winter_newsletter.pdf through http://www.questdiagnostics.com.

MEDLINEplus (2002, January 2, Updated). Neonatal cystic fibrosis screening. MEDLINEplus Health Information [On-line Information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003409.htm.

Drkoop (2001). Cystic fibrosis. Medical Encyclopedia [On-line information]. Available online at http://www.drkoop.com/conditions/ency/article/000107.htm through http://www.drkoop.com.

MEDLINEplus (2002, January 2, Updated). Trypsinogen. MEDLINEplus Health Information [On-line Information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003560.htm.

Biomedical Hypertext (1999 May 20, last update). Exocrine Secretions of the Pancreas. Colorado State University [On-line information]. Available online at http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/pancreas/exocrine.html through http://arbl.cvmbs.colostate.edu.

UPCMD (1998 – 2002). Cystic Fibrosis. University Pathology Consortium, LLC [On-line information]. Available online at http://www.upcmd.com/dot/examples/00218/description.html through http://www.upcmd.com.

Sainato, D., (2002, March). Genetic Testing for CF Going Mainstream? Clinical Laboratory News [Journal], Vol 28.

Peter Jacky, PhD, FACMG. Director of Cytogenetics and Molecular Genetics, Airport Way Regional Laboratory, Portland, OR.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Page 1088.