Role of liver function tests in predicting common bile duct stones in acute calculous cholecystitis.

BACKGROUND: The role of liver function tests (LFTs) in evaluating common bile duct (CBD) stones in patients with cholelithiasis has been studied widely. However, it is not clear whether these predictive models are useful in inflammatory gallstone disease.
METHODS: A review was undertaken of 385 consecutive patients admitted as an emergency for acute calculous gallbladder disease. The diagnosis of calculous cholecystitis was confirmed by ultrasonography or histological confirmation of acute or chronic inflammation of the gallbladder. Patients with obvious jaundice, defined as a bilirubin level above 80 micromol/l, and gallstone pancreatitis were excluded.
RESULTS: Some 216 patients met the inclusion criteria, of whom 28 (13.0 per cent) were found to have CBD stones. LFT results were not significantly different in patients with chronic, acute or complicated acute cholecystitis. Using several cut-off levels, gamma-glutamyl transpeptidase (GGT) had the highest specificity, positive predictive value and negative predictive value, comparable to a scoring system that combined all LFTs. Bilirubin was the least specific and predictive. A cut-off point for GGT at 90 units/l produced a sensitivity of 86 per cent (24 of 28), specificity of 74.5 per cent (140 of 188), and positive and negative predictive values of 33 per cent (24 of 72) and 97.2 per cent (140 of 144) respectively. This represented a one in three chance of CBD stones when the GGT level was above 90 units/l and a one in 30 chance when the level was less than 90 units/l.
CONCLUSION: Selection criteria based on GGT can be used in acute calculous cholecystitis to identify high-risk patients who would benefit most from further imaging to exclude choledocholithiasis.