Biliary Drainage is a gallbladder function test. It is performed by the physician and a certified laboratory technician during the examination. A small tube is inserted into your duodenum (the first part of the small intestine) at the time of your EGD. You are then given an intravenous injection of medication called C.C.K. which stimulates your gallbladder to contract and squirt bile out into the intestine.
The bile is collected through the tube in your duodenum, measured, and taken to the laboratory for analysis. This helps to determine whether or not you have a diseased gallbladder.
To read more about the EGD procedure, click here.