Microscopic examination of bile directly collected during endoscopic cannulation of the papilla

The usefulness of microscopic examination of pure bile directly collected from the biliary tract during endoscopic retrograde cholangiography and without hormonal simulation was prospectively evaluated in 72 patients. According to clinical, biochemical, ultrasonographic, and radiographic data, the patients were separated into two groups: group 1, patients with proven stones (N=50), and group 2, patients with suspected microlithiasis presenting symptoms suggestive of cholelithiasis but without evidence of macroscopic stones at echography or cholangiography (N=22). Cholesterol crystals and/or bilirubinate granules were observed (eg, positive examination) in the bile of 41 of the 50 patients of group 1 (82%). Among patients of group 2, seven (32%) had a positive bile examination: cholecystectomy (N=2) or endoscopic sphincterotomy (N=5) disclosed minute stones in all cases. In the 15 patients of group 2 with a negative bile examination, cholecystectomy (N=3), sphincterotomy (N=2), and clinical (and/or echographic) 20-month follow-up (N=9) revealed biliary lithiasis in only one patient, in whom recurrent cholangitis led to disclosure of one bile duct stone. According to these results microscopic examination of bile samples collected during endoscopic retrograde cholangiography exhibited a sensitivity and a specificity for cholelithiasis recognition of 82.7% and 100%, respectively, with a positive predictive value of 88%. We conclude that the accuracy of this method makes it useful to investigate and manage patients with suspected microlithiasis.