Laparoscopic cholecystectomy: laboratory predictors of choledocholithiasis

Liver function tests (LFTs) are most often employed to select patients for preoperative endoscopic retrograde cholangiography (ERC) and therapeutic sphincterotomy. Although ERC accurately detects CBD stones, the associated financial costs and potential morbidity argue against its indiscriminate use. We analyzed the value of LFTs to predict CBD stones in patients treated by laparoscopic cholecystectomy (LC). CBD stones were identified in 41 of 660 patients (6.2%) treated by LC during the study period (January 1991 to May 1993). CBD stones were identified by preoperative ERC in 19 of 33 patients (57.6%); by operative cholangiography in 18 of 289 patients (6.2%), and by postoperative ERC in 4 patients. In patients with CBD stones, there was a significant difference in alkaline phosphatase, total bilirubin, SGPT, and SGOT (P < 0.001). The positive predictive value (PPV) of a value > normal at admission was 5%-19%; and immediately before operation was 9%-36%. The PPV of a value > 2X normal was 30%-47%. Alkaline phosphatase and total bilirubin were independent predictors of CBD stones. If both were greater than twice normal, there was a 55 per cent incidence of CBD stones. Our analysis suggests that patients with greater than twice normal liver function tests have a sufficient incidence of CBD stones to warrant ERC. Patients without both these criteria should be managed by laparoscopic CBDE, with postoperative endoscopic stone retrieval for the failures of laparoscopic CBDE.