What are the Different Medical Coding Classification Systems?

Medical coding classification systems are groups of codes that correspond to individual procedures and diagnoses. They are used to accurately track information about diseases and health conditions in patient records and play a role in the medical billing process.

Medical coding classification systems aren’t just used by hospitals and care facilities. Government health programs and private insurers and also use them for a variety of purposes, including statistical analysis of diseases and procedures, claims and reimbursement, tracking outbreaks and with decision support systems.

Under the larger umbrella of medical coding classification systems, there are different categories that are used for specific purposes. For instance, diagnostic codes are used by care providers to classify diseases and symptoms, while procedural codes are used to identify surgical or medical procedures. Identifying the category that a medical coding system falls under can help you better understand its purpose and function.

The following list provides a brief overview of some classification systems used in the medical billing and coding field.

ICD-11 is the latest revision of the International Classification of Diseases (ICD) and is intended to replace ICD-10 as the new global standard for diagnostic codes. ICD-11 went into use in January 2022 and is used to meticulously classify everything from diseases to various symptoms. It also recodifies the classification area of some diseases, expands the definitions for sexual health and includes new entries for immune system and sleep-wake disorders, among other new diagnoses.

The ICD-10-CM is the clinical modification (CM) of the previous version of the ICD, ICD-10. This version of the ICD is designed to be used in a clinical setting and contains a level of detail that meets reporting needs within the United States. ICD-10-CM also differs from the standard ICD-10 codes in granularity. The codes in ICD-10-CM are more detailed and are especially useful for clinical, outpatient applications because they allow for clarification about the severity of a disease or condition.

The ICD-10-PCS is the procedural-focused version of the ICD, ICD-10. Unlike the ICD-10-CM, which is meant for more detailed classification of diseases and conditions, the ICD-10-PCS contains more detailed codes for procedures and equipment and is used for inpatient settings.

CPT stands for Current Procedural Terminology and is used to report diagnostic, surgical and medical procedures to relevant parties. CPT is a procedural medical coding classification system, meaning that it identifies the procedures that doctors and other care providers perform to help their patients. Its primary purpose is to communicate these procedures in a standardized way for administrative and analytical uses.

The Healthcare Common Procedure Coding System Level II, or HCPCS, is based on CPT and is used to code non-physician services that are not included in the CPT jurisdiction such as ambulances, drugs and prosthetics.