Chymotrypsin fecal

Although all pancreatic enzymes are inactivated during intestinal transit, fecal outputs of several enzymes correlate with pancreatic enzyme secretion. Fecal chymotrypsin activity, which is comparatively stable in the lumen as well as in extracorporal fecal samples, can be measured by a commercially available photometric test kit. When performed on three consecutive days, this test detects severe pancreatic exocrine insufficiency, but sensitivity and specificity are low in mild-to-moderate cases. In addition, the test does not differentiate between porcine and human chymotrypsin, so that pan-creatin supplements need to be discontinued 5 days prior to the test. For this reason, however, the test is able to monitor a patient s compliance in severe pancreatic insufficiency appar-endy refractory to enzyme treatment. Patients... 

Fecal elastase 1 concentration can be measured by an ELISA test kit using an antibody specific for the human enzyme pancreatin supplements do not interfere with this pancreatic function test and need not be discontinued. Although measurement of fecal elastase 1 excretion appears to be somewhat more sensitive than fecal chymotrypsin, its specificity and positive predictive value are similarly low, and falsepositive results can be expected in patients with intestinal diseases. Conversely, mild-to-moderate stages of pancreatic exocrine insufficiency cannot be diagnosed reliably. 

Direct tests of secretory function such as fecal chymotrypsin and elastase 1 are the tests of first choice if the main diagnostic goal consists of noninvasive confirmation of chronic pancreatitis. Indirect tests may be preferred, however, if the main goal is to verify maldigestion (which needs not be due to loss of pancreatic secretory capacity) or to optimize enzyme treatment. For patients for whom noninvasive direct or indirect tests are negative or equivocal and diagnosis or exclusion of pancreatic exocrine insufficiency appears relevant, the invasive secretin-cerulein (SC) test should be considered. 

Melzi d Eril GV, PoUini E, Moratti R, Sprovieri G, Tocchini M, Galeazzi M. Proposed reference values for fecal chymotrypsin as measured photometrically. Clin Chem 1985 31 1088-9. 

Amino acid consumption test -Fecal chymotrypsin ... 

Enzyme replacement for exocrine pancreas insufficiency must be adjusted on an individual basis considering age, body weight, weight for height, growth rate, fat intake, supplementary energy needs (particularly for pulmonary function), and clinical as well as laboratory evidence of malabsorption. Clinical symptoms include abdominal pain, distension, intolerance of fatty foods, and character of stools (consistency, number, odor). A more objective assessment involves microscopic examination of stool for neutral and split fats, measurement of fecal chymotrypsin or elastase [96]. 

Figure 48-8 Fecal excretion (mean and SD) of chymotrypsin, fat, and immunoreactive elastase during a 24-hour collection period in 12 patients with cystic fibrosis and steatorrhea with and without enzyme replacement therapy. (From Stein JJung M, Sziegoleit A, Zeuzem S, Caspary WF, Lembcke B. immunoreactive elastase / c//njco/ eva/uat/on of a new non-invasive test of pancreatic function, din Cbem 1996 42 222 6.)...

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