A comparison of two methods to measure amylase, lipase, trypsin, and chymotrypsin activity and the effect of freezing and thawing on enzyme activities in pancreatic juice

Assessment of exocrine pancreatic function in children and adolescents with direct and indirect testing

The exocrine pancreas plays an important role in digestion. Understanding of the physiology and regulation of exocrine function provides insight into disease processes and basis of functional testing. Specifically, exocrine pancreatic insufficiency (EPI) can cause maldigestion and thus a proper assessment of exocrine pancreatic function is important. There are indirect and direct methods for evaluating pancreatic function. Indirect methods are varied and include stool, serum, urine, and breath tests. Fecal elastase is a commonly used indirect test today. Direct methods involve stimulated release of pancreatic fluid that is collected from the duodenum and analyzed for enzyme activity. The most used direct test today is the endoscopic pancreatic function test. Indirect pancreatic function testing is limited in identifying cases of mild to moderate EPI, and as such in these cases, direct testing has higher sensitivity and specificity in diagnosing EPI. This review provides a comprehensive guide to indirect and direct pancreatic function tests as well as an in-depth look at exocrine pancreatic function including anatomy, physiology, and regulatory mechanisms.

Analysis of amylase in duodenal juice - Automated kinetic spectrophotometric analysis versus manual colorimetric endpoint assay

OBJECTIVE

The measurement of duodenal amylase by a colorimetric end-point assay has been the most used method for amylase activity analyses. The method is manual, time consuming and dependent on specialized equipment. In this study, we compare an automated kinetic spectrophotometric method for pancreatic amylase measurement in duodenal juice with a standardized colorimetric end-point assay.

METHODS

We used specimen of duodenal juice at random from a biobank obtained by short endoscopic secretin test in patients with suspected exocrine pancreatic failure of different reasons. Duodenal juice was tested for amylase activity with a conservative manual colorimetric endpoint assay (Phadebas Amylase test, Magle AB) and an automated enzymatic kinetic spectrophotometric method using standard reagents for pancreatic amylase activity for Cobas c111 (Roche Diagnostics).

RESULTS

52 samples for assay of amylase were analyzed in pairs. Correlation between measurements with the two methods was r = 0.99 (p < 0.001), linear regression 0.99 (p < 0.001).

CONCLUSION

Quantification of duodenal amylase activity with automated spectrophotometry has excellent correlation to measurements made by the manual method. This allows for standardized, center independent analyses of duodenal amylase for the assessment of acinar pancreatic function.

Determination of plasma trypsin-like activity in healthy subjects, patients with mild to moderate alcoholic chronic pancreatitis, and patients with nonjaundice pancreatic cancer

Trypsin-like activity is released after stimulation of the exocrine pancreas. We investigated under basal conditions and after stimulation by a meal whether patients suffering from pancreatic disorders differ with respect to plasma trypsin-like activity (PTLA). In 45 subjects (healthy volunteers: n = 18, mild/moderate alcoholic chronic pancreatitis: n = 16, nonjaundice pancreatic cancer n = 7, and calcifying chronic pancreatitis: n = 4), basal and postprandial levels of PTLA were measured over a period of 2 hours. Basal plasma levels were similar in the first 3 groups. After stimulation, healthy volunteers and patients with pancreatic cancer showed significant decreases in trypsin-like activity; however, plasma levels did not decrease in patients with mild/moderate chronic pancreatitis (P < .001). Healthy individuals demonstrate a consistent decrease in postprandial trypsin-like plasma activity. This response is not altered in patients with pancreatic cancer, and it is not seen in patients with mild/moderate alcoholic chronic pancreatitis.