How often are liver function tests normal in acute biliary pancreatitis?

Background: The biochemical markers of a biliary etiology of acute pancreatitis (AP) include an ALT elevation of more than 3 times the upper range of normal (ULN) and a serum total bilirubin greater than 3 mg%. Objectives: To analyze the frequency of normal LFTs (Bilirubin, ALP, ALT, and AST) in patients with biliary AP. Design: In this prospective study data collected for other ongoing studies on AP in the division of Gastroenterology in the last 20 years were analyzed. Material and Methods: Serum total Bilirubin, AST, ALT, and ALP levels in 269 patients with biliary AP out of 728 cases of AP of various etiologies were analyzed. The biliary etiology was confirmed on the basis of gallstones documented by transabdominal US or at surgery. Results: We noted normal bilirubin, AST, ALT, and ALP levels in 14.5%, 12.3%, 11.2%, and 26.4% of cases of acute biliary pancreatitis respectively. When all the 4 laboratory tests were considered collectively, the incidence of normal values was 10.4%. We also noted an ALT elevation of <3 x ULN in 16.7% of cases of biliary AP and 43.5% of cases had a T. Bilirubin level of less than 3 mg %. Conclusions: Almost 15 to 20% of patients with biliary AP manifest with normal LFTs. The clinician should not exclude a biliary etiology solely on the basis of normal LFTs.