ICD-9-CM and ICD-10-CM are diagnosis and procedure coding systems. ICD-10-CM codes consist of up to seven characters compared to the three to five characters in ICD-9-CM, allowing for more detailed coding. The first character of an ICD-10-CM code is alphabetic while characters two through seven can be alphabetic or numeric. The compliance date for covered entities to transition to using ICD-10-CM codes is October 1, 2013.