Question: What diagnosis should I submit to support Synvisc administration? Rhode Island Subscriber Answer: Diagnosis coding possibilities for the knee include 715.1x (Osteoarthrosis, localized, primary), but 715.3x (Osteoarthrosis, localized, not specified whether primary or secondary) is usually the go-to code because physicians do not typically state whether the OA is "localized, primary" or "localized, secondary." You could also look at .715.16 (Osteoarthrosis, localized, primary; lower leg), 715.26 (Osteoarthrosis, localized, secondary; lower leg), 715.36 (Osteoarthrosis, localized, not specified whether primary or secondary; lower leg), and 715.96 (Osteoarthrosis, unspecified whether generalized or localized; lower leg). You should always try for the highest degree of specificity, so make sure your physician documents the OA clearly. Your carrier's policy might allow for other diagnoses (sometimes even for the ankle or hip), so check your local guidelines. Be sure your physician's documentation supports the diagnosis you submit. For the procedure, submit either 20610 (Arthrocentesis, aspiration and/or injection; major joint or bursa [e.g., shoulder, hip, knee joint, subacromial bursa]). Then verify whether your physician administered bilateral injections. If so, append the appropriate modifier to the procedure code. Depending on your carrier's preference for bilateral reporting, use modifier 50 (Bilateral procedure) or modifiers LT (Left side) and RT (Right side). Precert note: Work with the carrier to obtain precertification for the procedure. Remember that completing precertification can take up to two months, so be sure your patient realizes this and is prepared to pay for the Synvisc injection herself if her carrier does not reimburse. Have the patient sign an advance beneficiary notice ahead of time if she-ll be paying for the injection herself. If your physician administers the Synvisc during a separately identifiable office visit, append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure or other service) to the E/M code (such as 99203, Office or other outpatient visit for the evaluation and management of a new patient ...). Reader Questions and You Be the Coder were reviewed by Heidi Stout, CPC, CCS-P, director of orthopedic coding services at The Coding Network LLC; and Bill