The true value of serum elastase-1 in endoscopic retrograde cholangiopancreatography (ERCP)

BACKGROUND: The routine use of serum elastase-1 in patients, pre- and post-endoscopic retrograde cholangiopancreatography (ERCP), has been strongly supported but not sufficiently correlated with diagnosis, patient outcome/prognosis, or routine markers such as serum amylase. The value of serum elastase-1 post-ERCP, as far as clinical diagnosis and prognosis is concerned, was tested and compared with serum amylase in terms of sensitivity, specificity, positive prognostic value (PPV), and negative prognostic value (NPV). METHODS: In a prospective study of 38 consecutive patients undergoing ERCP, we assessed the following biochemical parameters 24 h before ERCP and 2 and 18 h after ERCP: alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (gamma-GT), alkaline phosphatase (ALP), amylase (AMS), lactate dehydrogenase (LDH), and pancreatic elastase-1. RESULTS: Statistically significant changes were found between pre-ERCP and 18-h post-ERCP in elastase-1 (P=0.009), amylase (P=0.016), gamma-GT (P=0.04), and ALP (P=0.04). Changes between 2-h and 18-h post-ERCP in all parameters tested were not statistically significant. No statistical significance was found between any biochemical parameter and specific ERCP diagnosis. CONCLUSIONS: This study showed that 2-h post-ERCP serum elastase-1 was 100% specific for post-ERCP pancreatitis or other underlying severe pathology while, at the same time, amylase was only 50% specific. The specificity of serum elastase-1 still remained high (87.5%) 18-h post-ERCP, while amylase only had a specificity of 25% at that time. In contrast, amylase had a sensitivity of 83.3 and 90% in the 2-h and 18-h post-ERCP serum samples, while elastase-1 only had a sensitivity of 56.7 and 73.3%, respectively.