Question: What procedures should I match with 75980 and 75982? Washington Subscriber Answer: You typically report 75980 (Percutaneous transhepatic biliary drainage with contrast monitoring, radiological supervision and interpretation) with 47510 (Introduction of percutaneous transhepatic catheter for biliary drainage). In the 47510 procedure, often called "external drainage," the physician introduces a catheter into the liver, positioned above the obstruction. This position allows the bile to drain outside the body. The physician uses fluoroscopy and contrast for guidance, such as visualizing the intrahepatic bile ducts. You typically report 75982 (Percutaneous placement of drainage catheter for combined internal and external biliary drainage or of a drainage stent for internal biliary drainage in patients with an inoperable mechanical biliary obstruction, radiological supervision and interpretation) with 47511 (Introduction of percutaneous transhepatic stent for internal and external biliary drainage). The procedure described by 47511, also known as "internal-external drainage," also requires the physician to introduce a catheter into the liver, but the physician places the catheter past the obstruction, allowing bile to drain into the small intestine. Part of the catheter may also extend outside the body.