What Are the Different Types of Medical Coding Classification Systems?

Two common medical coding classification systems are in use — the International Classification of Diseases (ICD) and the Current Procedural Terminology (CPT). ICD is the standard international system of classifying mortality and morbidity statistics, and it’s used by more than 100 countries. The system is used by health care facilities to define diseases and allocate resources to provide care. According to the World Health Organization (WHO), 70% of the world’s health care expenditures are allocated using ICD. The current version, ICD-10, features more than 68,000 codes for infections and parasitic diseases, neoplasms, and congenital malformations, as well as diseases of the digestive system, respiratory system, and nervous system.

ICD codes are alphanumeric designations given to every diagnosis, description of symptoms and cause of death attributed to human beings. These classifications are developed, monitored, and copyrighted by the World Health Organization (WHO). In the U.S., the NCHS (National Center for Health Statistics), part of CMS (Centers for Medicare & Medicaid Services) oversees all changes and modifications to the ICD codes, in cooperation with WHO.

The ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) coding system, connects health issues that arise in patients, by using three- to seven-digit alphanumeric codes to indicate signs, symptoms, diseases, conditions, and injuries to payers injuries, diseases, and conditions. These codes are used in conjunction with CPT (procedural) codes to record services rendered by a provider to a patient and is documented in the medical record and then reported to a payer for reimbursement.

Note: Medical necessity is the overarching criteria for a service and the diagnosis code is used to indicate medical necessity in conjunction with a CPT code.

On Oct. 1, 2014, ICD-10 was implemented and replaced its predecessor, ICD-9-CM, as the standard coding system for the U.S.  The 11th revision process is currently underway, and ICD-11 will be finalized in 2018.

CPT (Current Procedural Terminology) codes are published by the American Medical Association, and there are approximately 10,000 CPT codes currently at use. The U.S. and other countries use the fourth edition and they were designed to provide a uniform data set that could be used to describe medical, surgical, and diagnostic services rendered to patients.

CPT codes are five-digit alphanumeric codes and consist of five numbers and occasionally may have four numbers and letter, depending on the type of service. CPT codes are used to identify services provided to patients such as, medical, surgical, diagnostic, and radiological services. These codes are submitted with ICD-10 codes on claim forms to payers and that is what is used to determine reimbursement to a provider/facility.

The AMA has implemented the CPT Editorial Panel, which meets three times a year, which reviews and discusses issues that are relevant to any new or upcoming technology and identified problems encountered with any procedure and how it relates to a specific code.

Final Thoughts

Medical billing and coding professionals and providers use these two classifications systems on a daily basis, and they are the “bibles” and building blocks for this industry. Every year, it is mission critical for billers and coders to obtain the new versions of both these code sets to stay abreast of any changes to codes in either of these classification systems, otherwise they will risk denied claims and potential compliance issues.

Happy Coding!