Diagnostic Accuracy of Fecal Elastase-1 Test for Pancreatic Exocrine Insufficiency: A Systematic Review and Meta-Analysis.

Introduction: Pancreatic exocrine insufficiency (PEI) results from a reduction in pancreatic secretion of enzymes, leading to malabsorption of nutrients, intestinal symptoms, nutritional deficiencies and related comorbidities. The diagnosis of pancreatic exocrine insufficiency should be based on digestive tests, mainly the coefficient of fat absorption (CFA), based on the quantification of 72 h fecal fat excretion (FFE). However, this test is rarely performed in clinical practice. Fecal elastase-1 (FE-1) is a simple and widely used alternative. This meta-analysis evaluates the diagnostic accuracy of fecal elastase-1 for the diagnosis of PEI diagnosed by CFA or 72h-FFE.

Methods: A systematic search of databases was performed to identify studies evaluating fecal elastase-1 and CFA/FFE for the diagnosis of pancreatic exocrine insufficiency. Inclusion criteria required original studies with data on sensitivity, specificity and other diagnostic metrics. Two independent reviewers performed data extraction and quality assessment using the QUADAS-2 tool. Pooled sensitivity, specificity, likelihood ratios and diagnostic odds ratio (DOR) were calculated and heterogeneity was assessed using I-squared tests.

Results: Thirteen studies with 888 patients were included. Fecal elastase-1 at a cut-off of 200 μg/g showed a pooled sensitivity and specificity of 0.94 and 0.69, respectively, with a DOR of 35.27. Lowering the cut-off to 100 μg/g improved specificity to 0.82 but decreased sensitivity to 0.88. Subgroup analyses showed different diagnostic performance in different clinical contexts, with higher sensitivity in cystic fibrosis (0.98) and higher specificity in chronic pancreatitis (0.81). The positive and negative predictive values are limited in situations with low and high probability of pancreatic exocrine insufficiency, respectively.

Conclusions: Fecal elastase-1 is a sensitive and moderately specific diagnostic tool for pancreatic exocrine insufficiency and is suitable for initial screening in high-risk populations. However, its moderate specificity requires careful interpretation in lower risk settings.