(International Classification of Diseases and Related Health Problems) A classification of diagnostic codes in the medical field published by the World Health Organization (WHO). Stemming from the French Bertillon classification in the late 1800s, the WHO took over ICD in 1946. The three-volume ICD-9 CM (ICD-Version 9 Clinical Modifications) was introduced in 1979 and is also the HIPAA transaction code set. Physicians use Volumes 1 and 2 of ICD-9 CM for diagnostic codes and Current Procedural Terminology (CPT) codes for their procedures. Volume 3 of ICD-9 CM is used by hospitals for procedure codes. ICD-10, ICD-10 CM and ICD-10 PCS ICD-Version 10 has been used for morbidity and mortality statistics worldwide since 1994 and in the U.S. since 1999. ICD-10 CM, introduced in 2002, replaces ICD-9 CM with a final adoption deadline of October 1, 2013, mandated by Health and Human Services (HHS). ICD-10 CM includes 68,000 diagnostic codes, five times more than ICD-9 CM. It expanded the code from five to seven characters, allowing alpha, except for U, in position four through seven (from ANN.NN to ANN.AAA A). ICD-10 (PCS) Procedural Coding System replaces Volume 3 of ICD-9 CM for hospital procedure codes. See SNOMED CT, LOINC and healthcare IT.