Comparison of Exocrine Pancreatic Function by Two Tubeless Tests in Fibrocalculous Pancreatic Diabetes (FCPD) and Insulin Dependent Diabetes Mellitus (IDDM)

Two tubeless tests of exocrine pancreatic function, the NBT-PABA test and faecal chymotrypsin (FCT) assay were compared. Thirteen patients with Fibrocalculous Pancreatic Diabetes (FCPD), 12 patients with Insulin Dependent Diabetes Mellitus (IDDM) and 13 control subjects were studied. Using a PABA excretion value < 43%, 100% of FCPD patients and 58.3% of IDDM patients had abnormal exocrine pancreatic function. Using an FCT value < 5.9 units/gram, 92.3% of FCPD patients and 25% of IDDM patients had exocrine pancreatic insufficiency. Thus both PABA and FCT tests were found to be useful in differentiating the two diabetic groups from controls but were poor discriminators of FCPD and IDDM forms of diabetes. Comparing the two tests, the FCT test has a slightly lower sensitivity, but is simpler and considerably cheaper than PABA test and hence suitable for routine clinical use.