ICD-10 is the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD), a medical classification list by the World Health Organization (WHO). In short, it is a system that is used to assign numeric codes to diagnoses of illness or injury, commonly used for billing purposes.
This version of the classification and coding system was first introduced in 1994; countries around the world have gradually adopted it in the years since. Originally, all organizations in the United States dealing in health information and diagnosis were required to complete conversion to the 10th revision of this system by October 1, 2011. This deadline has been delayed a number of times, and is currently set at October 1, 2015.
What this means to health care professionals is the necessity of understanding a new, more specific medical coding system. Where ICD-9 contained approximately 17,000 diagnostic codes, the U.S. ICD-10 Clinical Modification (ICD-10-CM), for instance, includes some 68,000 codes. The U.S. also has the ICD-10 Procedure Coding System (ICD-10 PCS), a coding system that covers 76,000 codes not used by other countries.
While the Federal mandate for transition allows for “cross-walks,” or conversion of the ICD-9 code to ICD-10 codes via electronic mapping or other method, it is important to understand the process by which a diagnosis is reached, and how the codes are applied, in order to accurately submit billing claims to health insurance providers on behalf of patients, to bill patients directly, and to correctly document patient data in charts, EHR systems and other medical files.
The basic structure of the ICD-10 code is as follows: Characters 1-3 (the category of disease); 4 (etiology of disease); 5 (body part affected), 6 (severity of illness) and 7 (placeholder for extension of the code to increase specificity.)