The one-year grace period allowed by the Centers for Medicare and Medicaid Services (CMS) and the American Medical Association (AMA) for unspecified ICD-10-CM (diagnosis) codes on claims filed under the Medicare Part B fee schedule, as long as the correct level of code specificity is used, ended on October 1. Although there are rare instances when unspecified ICD-10 codes are appropriate, physician practices doing so after October 1 may experience an increase in post-payment audits and quality reporting errors. In addition, 2,305 new ICD-10-CM and 3,836 new ICD-10-PCS (procedure) codes became effective on October 1, 2016. Physicians are encouraged to document patient diagnoses with precision, and to review the Local Coverage Determination (LCD) and National Coverage Determination (NCD) medical necessity policies for coding changes.