Difference Between ICD 9 - ICD 10 Basic Information about ICD 9: The United States Implemented ICD 9 in 1979. But most of the countries moved to ICD 10 several years ago, it’s time for United States medical history to reflect modern Medical terms. Difference between ICD 9 – ICD 10 Code set differences ICD-9-CM codes are very different than ICD-10-CM/PCS code sets: There are nearly 19 times as many procedure codes in ICD-10-PCS than in ICD-9-CM volume 3 There are nearly 5 times as many diagnosis codes in ICD-10-CM than in ICD-9-CM ICD-10 has alphanumeric categories instead of numeric ones The order of some chapters have changed, some titles have been renamed, and conditions have been grouped differently ICD-9-CM Diagnosis Codes ICD-10-CM Diagnosis Codes No Laterality Laterality – Right or Left account for >40% of codes 3-5 digits First digit is alpha (E or V) ...