Understanding Medical Diagnosis Codes: Structure & Uses

A medical diagnosis code consists of a string of characters (either all numbers or a mix of numbers and letters), which is used to:

- classify diseases as per a coding scheme

- record patients' diagnoses in digital medical records

- send data to health insurers and other healthcare organizations

- report quality measures

- manage patient populations

- conduct clinical research

Some of the most common coding schemes include:

- International Classification of Diseases (ICD), maintained by the World Health Organization (WHO).

- Current Procedural Terminology (CPT), maintained by the American Medical Association (AMA).

- Hierarchical Code System (HCR), maintained by the Agency for Healthcare Research and Quality (AHRQ).

- Systematized Nomenclature of Medicine (SNOMED CT), maintained by the International Health Terminology Standards Development Organization (IHTSDO).