The BT-PABA/PAS test in tropical diabetes

A ‘screening’ test is needed to identify patients with chronic pancreatitis among diabetics in tropical field surveys. We have examined the potential diagnostic yield of the BT-PABA/PAS test of exocrine pancreatic function in this setting. The recoveries of both PABA and PAS in eight healthy controls from Madras, south India, were lower than in controls from Manchester, north west England (mean ± S.D., 51 ± 11 vs. 79 ± 7%, P < 0.001 for PABA; 52 ± 11% vs. 81 ± 7%, P < 0.001 for PAS) but the % PABA/PAS excretion index (PEI) was similar (0.96 ± 0.14 vs. 0.96 ± 0.06). Using a cut-off value of 0.75 for the PEI in a study group including eight patients with chronic pancreatitis and 26 with primary forms of diabetes, test sensitivity was 75%, specificity 92%, positive predictive value 75%, negative predictive value 92% and efficiency 88%.