Special considerations in interpreting liver function tests.

TLDR

Interpreting common liver function tests is fraught with pitfalls, including normal results in chronic liver disease, demographic variations in normal ranges, and misdiagnoses such as alcoholic hepatitis versus biliary disease or transient enzyme elevations after bile duct stones. Overall hepatic function can be evaluated using albumin, bilirubin, and prothrombin time within the modified Child‑Turcotte grading system.

Abstract

A number of pitfalls can be encountered in the interpretation of common blood liver function tests. These tests can be normal in patients with chronic hepatitis or cirrhosis. The normal range for aminotransferase levels is slightly higher in males, nonwhites and obese persons. Severe alcoholic hepatitis is sometimes confused with cholecystitis or cholangitis. Conversely, patients who present soon after passing common bile duct stones can be misdiagnosed with acute hepatitis because aminotransferase levels often rise immediately, but alkaline phosphatase and gamma-glutamyltransferase levels do not become elevated for several days. Asymptomatic patients with isolated, mild elevation of either the unconjugated bilirubin or the gamma-glutamyltransferase value usually do not have liver disease and generally do not require extensive evaluation. Overall hepatic function can be assessed by applying the values for albumin, bilirubin and prothrombin time in the modified Child-Turcotte grading system.