What is the difference between ICD-10-CM and ICD-10-PCS?

ICD–10–CM Diagnosis Codes
The CDC’s National Center for Health Statistics (NCHS) developed the ICD–10–CM code set, following a voluntary consensus-based process and working closely with specialty societies to ensure clinical utility and subject matter expert input into the process of creating the clinical modifications, with comments from a number of prominent specialty groups and organizations that addressed specific concerns or perceived unmet clinical needs encountered with ICD–9–CM.

NCHS also had discussions with other users of the ICD–10 code set, specifically nursing, rehabilitation, primary care providers, the National Committee for Quality Assurance (NCQA), long-term care and home health care providers, and managed care organizations to solicit their comments about the ICD–10 code set. There are approximately 68,000 ICD–10–CM codes. ICD–10–CM diagnosis codes are three to seven alphanumeric characters. The ICD–10–CM code set provides much more information and detail within the codes than ICD–9–CM, facilitating timely electronic processing of claims by reducing requests for additional information.

ICD–10–PCS Procedure Codes
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. The cooperating parties and especially CMS have made it very clear that there is no intention for ICD-10-PCS to replace CPT for the identification of physician work. 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.

CPT remains the procedure coding standard for physicians, regardless of whether the physician services were provided in the inpatient or outpatient setting. Any third party payer asking for Volume 3 procedure codes to be submitted along with CPT codes for outpatient services is in violation of HIPAA regulations and subject to fines by CMS.

Some preliminary inpatient hospital testing of ICD-10-PCS has indicated that the new procedure coding system is problematic to learn for both experienced and inexperienced coders.

ICD–10–PCS is sufficiently detailed to describe complex medical procedures. This becomes increasingly important when assessing and tracking the quality of medical processes and outcomes, and compiling statistics that are valuable tools for research. ICD–10–PCS has unique, precise codes to differentiate body parts, surgical approaches, and devices used. It can be used to identify resource consumption differences and outcomes for different procedures, and describes precisely what is done to the patient. ICD–10–PCS codes have seven alphanumeric characters and group together services into approximately 30 procedures identified by a leading alpha character. There are 16 sections of tables that determine code selection, with each character having a specific meaning. No SSO has developed, adopted, or modified a standard code set that is suitable for reporting medical diagnoses and hospital inpatient procedures for purposes of administrative transactions.