Pancreatic Function Tests

Published on 22/03/2015 by admin

Filed under Pediatrics

Last modified 22/04/2025

Print this page

This article have been viewed 1060 times

Chapter 340 Pancreatic Function Tests

Steven L. Werlin

Pancreatic function can be measured by direct and indirect methods. An indirect test, the measurement of fecal elastase, which has become the standard screening test for pancreatic insufficiency, has a sensitivity and specificity >90%. Falsely abnormal results can occur in many enteropathies. The activity of other pancreatic enzymes in stool is now rarely measured.

Classically, a triple-lumen tube was used to isolate the pancreatic secretions in the duodenum. Measurement of bicarbonate concentration and enzyme activity (trypsin, chymotrypsin, lipase, and amylase) is performed on the aspirated secretions. This test is cumbersome and infrequently used. The most commonly used direct test is collection of pancreatic juice at endoscopy after stimulation with secretin and/or cholecystokinin.

A 72-hr stool collection for quantitative analysis of fat content is the gold standard for the diagnosis of malabsorption. The collection is usually performed at home, and the parent is asked to keep a careful dietary record, from which fat intake is calculated. A pre-weighed, sealable plastic container is used, which the parent keeps in the freezer. Freezing helps to preserve the specimen and reduce odor. Infants are dressed in disposable diapers with the plastic side facing the skin so that the complete sample can be transferred to the container. Normal fat absorption is >93% of intake. The presence of fat malabsorption does not differentiate between pancreatic dysfunction and enteropathies, such as celiac disease. Qualitative examination of the stool for microscopic fat globules can give false-positive and false-negative results.

Pancreatic function can also be measured by a breath test using ¹³C-triolein as the substrate. This test has not gained widespread acceptance because it is relatively insensitive in detecting mild cases of pancreatic insufficiency, and detection of ¹³CO₂ requires a mass spectrophotometer that is not generally available.

Beharry S, Ellis L, Corey M, et al. How useful is fecal pancreatic elastase 1 as a marker of exocrine pancreatic disease? J Pediatr. 2002;141:84-90.

Pfefferkorn M, Fitzgerald J, Croffie J, et al. Direct measurement of pancreatic enzymes: a comparison of secretagogues. Dig Dis Sci. 2002;47:2211-2216.

Walkowiak J, Nousia-Arvanitakis S, Henker J, et al. Indirect pancreatic function tests in children. J Pediatr Gastro Nutr. 2005;40:107-114.

Related

Nelson Textbook of Pediatrics Expert Consult