Question

What are the structural differences between ICD-9-CM and ICD-10-CM/PCS, including the meaning of CM vs. CM/PCS?

Answer 1

Basically, the ICD is an international classification of diseases, and the "9" or "10" designations mean that each one is the 9th or 10th or its kind. The CM means "clinical modification".

On the other hand, ICD-10-PCS (Procedure Coding System) is currently designated to replace Volume 3 of ICD-9-CM for hospital inpatient use only. ICD–10–PCS has no direct relationship to the basic ICD–10 diagnostic classification, which does not include procedures, and has a totally different structure from ICD–10–CM. According to HealthCare Information Management, Inc. (HCIM), “Its only intention is to identify inpatient facility services in a way not directly related to physician work, but directed towards allocation of hospital services.”

Talking about differences, ICD-10 has more classification of diseases as there are over 72000 procedural codes, where ICD-9 has over 14000 codes.
ICD-9 codes contain three to five digits beginning with either a number or a letter, with a decimal point placed after the third digit, and the ICD-9 book indicates the level of specificity for each code. ICD-10 codes, on the other hand, are seven digits in length.
The first three digits are like the corresponding ICD-9 code, with a decimal point after the third digit. But the digits that follow the decimal point have specific meaning. For medical and surgical procedures, for example, the digits that follow are specific to body part, surgical approach, and other qualifiers needed for billing. Similarly, the ICD-10 CM codes that represent diagnosis codes also have seven digits.