Chapter Two

International Classification of Diseases, 9^th Revision (ICD-9) and ICD-10 both have a Table of Contents. ICD-10, there are 21 disease classifications listed, which incorporate ICD-9 V codes and E codes. "External caused injuries" and "external causes of morbidity" are concentrated in ICD-10. Billers and coders would use ICD-10 in a manner similar to using ICD-9. The ICD-10 Alphabetic Index directs physicians to an S code. S codes are used for Injury, Poisoning and Certain Other Consequences of External Causes. In effect, physicians are directed to the ICD-9 equivalent of an E code. It should be noted that ICD-10 has a separate Alphabetic Index to External Causes. A review of the index shows that there are no direct references to S codes. The lack of a one-to-one relationship should be a red flag that using a simple crosswalk tool will not allow physicians to understand ICD-10. ICD-10 represents an increase of over 700" in the number of codes versus ICD-9.