Utility of Fecal Elastase-1 to diagnose severe exocrine insufficiency in chronic pancreatitis: Real world experience.

ABSTRACT

INTRODUCTION: Quantitative fecal fat estimation is the gold standard test to diagnose steatorrhea (fecal fat >7 g/day) in chronic pancreatitis (CP), but cumbersome and inconvenient. So, fecal elastase-1 (FE) is proposed as a good alternative but the data on the diagnostic utility of FE to diagnose steatorrhea is variable. METHODS: This retrospective study included adult CP patients evaluated with both 24-h fecal-fat and FE tests within a 3-month period. The objective was to evaluate the diagnostic performance of FE to diagnose steatorrhea and to evaluate the FE progression over 9-month period. RESULTS: Among the 147 included patients, the frequency of steatorrhea (fecal fat >7 g/day) was 34%. The sensitivity, specificity, and negative likelihood ratio (LR) of FE was 90%, 28.9% and 0.35 at cut-off of <100 µg/g stool to diagnose steatorrhea; and 96%, 11.3% and 0.35 at cut-off of <200 µg/g stool, respectively. The optimal cut-off of FE was <20 on receiver operating characteristic curve (sensitivity 66%; specificity 69%; positive LR 2.14). There was no statistically significant variation in FE levels over 9 months interval among a hundred patients. CONCLUSION: Compared to FE ≥ 200 µg/g stool, FE ≥ 100 can used to exclude steatorrhea (better specificity and negative LR). FE < 20 alone cannot replace fecal fat estimation to confirm steatorrhea but to be interpreted with clinical features. Repeat FE testing for exocrine insufficiency progression can be done at least a year later.