This is the 2019 Coding Book revised on 10.01.19, please be sure to check out our new 2020 Coding Book! A great quick reference for your office. Keep one in every exam room and most diagnosis codes and procedure codes will be at your finger tips. It also defines most CPT procedure codes and explains how to determine which 99xxx code for office visits to use for each different patient scenario. Defines many of the commonly used modifiers and indicates which procedures Medicare will allow for each diagnosis code.