Clarity on Laterality for ICD-10-CM Effective Oct. 1, 2016

New guidance is offered in the new ICD-10-CM for 2017 that is effective October 1, 2016 on laterality. There have been some questions on which side to assign codes when one side vs. another is being treated or addressed or repaired. These new guideline clarifications can be found below in blue:

B. General Coding Guidelines

13. Laterality

When a patient has a bilateral condition and each side is treated during separate encounters, assign the “bilateral” code (as the condition still exists on both sides), including for the encounter to treat the first side. For the second encounter for treatment after one side has previously been treated and the condition no longer exists on that side, assign the appropriate unilateral code for the side where the conditions still exists (e.g., cataract surgery performed on each eye in separate encounters). The bilateral code would not be assigned for the subsequent encounter, as the patient no longer has the condition in the previously treated site. If the treatment on the first side did not completely resolve the condition, then the bilateral code would still be appropriate.


Brian Boyce, BSHS, CPC, CPC-I, CRC, CTPRP is an AAPC-approved PMCC medical coding instructor, and ICD-10-CM trainer and the author of the AAPC CRC® curriculum. He has specialized in risk adjustment from the very beginnings of these models being utilized and has assisted large and small clients nationally. He has special interest in ethics, patient safety, disease management, and management and leadership of people. Brian is a veteran of Desert Storm, where he served on active duty with the US Air Force with a job specialty of Aeromedical Evacuation. He went into physician practice management and medical coding after an honorable discharge. He is the CEO of ionHealthcare® LLC, a company that specializes in healthcare consulting, risk adjustment coding, management & support services. For additional inquiries contact ionHealthcare® at