BACKGROUND: The purpose of this study was to determine the probability of choledocholithiasis from the association of clinical and laboratory indicators at two moments of the preoperative phase of cholecystectomy. METHODS: Between March 2001 and March 2002, 48 consecutive patients with cholelithiasis were submitted to cholecystectomy and intra-operative cholangiography (IOC). The patients were divided into two groups, with group A composed of 13 patients with choledocholithiasis and group B of 35 patients without this disease. They were investigated by clinical and laboratory indicators of choledocholithiasis, analyzed in two periods, taking as the cut point the 48 hours that preceded the surgery. Later on, these preoperative indicators were associated in the logistic regression equation in different combinations. RESULTS: Using the logistic regression equation, it was found that the association of two clinical indicators in both periods (jaundice and Murphy‘s sign) and two laboratory indicators (the cut level of gamma glutamyl transpeptidase and direct bilirubin 48 hours before the surgery) was the most suitable for predicting choledocholithiasis. The values obtained by this equation showed an agreement with groups A and B of 95.6%, and a disagreement of 4.4% (p= 0.0000007 and k = 0.89). This equation showed sensitivity of 92.3%, specificity of 97.0%, a positive predictive value of 92.3% and a negative predictive value of 97%. These values were close to those obtained by the CIO, which showed agreement with the groups studied of 95.8%, and disagreement of 4.2% (k = 0.90). CONCLUSION: The association of indicators of choledocholithiasis is recommended to establish the probability of there occurring choledocholithiasis associated with cholelithiasis. The use of this equation may provide better guidance for the diagnostic and therapeutic handling of this disease.
Predictive value; Choledocolithiasis; Cholangiography; Cholecystectomy
