Question: I am new to ASC coding, having worked previously in hospital outpatient departments. How am I supposed to code for bilateral procedures? Answer: One of the biggest differences between ASC and hospital outpatient department (HOPD) coding is how you indicate bilateral services, says Amy C. Pritchett, BSHA, CPC, CPC-I, CANPC, CASCC, CEDC, CASCC, CRC, CCS, CDMP, CMPM, ICDCT-CM, ICDCT-PCS, CMRS, C-AHI, who spoke at the American Academy of Professional Coders’ recent Healthcon. Don’t use modifier 50 for ASC claims, Pritchett reminded attendees. Instead of modifier 50, use modifier RT or LT. Medicare has recently begun to say that coders can put RT and LT if both sides are done but, like most coders we talk to, Pritchett recommends putting them on separate lines if you want to make certain your claims for bilateral services are paid. “If you’re a rebel, put your motorcycle jacket on, try it, and let me know how it goes” with putting RT and LT on the same line, she jokes.