Bile cytology. A routine addition to percutaneous biliary drainage.

Exfoliative cytology of bile aspirated from percutaneously placed combined external/internal biliary drainage catheters yielded positive results in 34% of 100 cases. There were no false-positive results. Bile cytology is a simple, inexpensive, and useful method which can establish a diagnosis of malignant biliary obstruction after catheter decompression.