Which coding system is primarily used for clinical documentation?

The International Classification of Diseases (ICD) is primarily used for clinical documentation because it provides a standardized way to classify and code all diagnoses, symptoms, and procedures recorded in conjunction with healthcare delivery. The ICD coding system is essential in documenting health conditions, tracking disease prevalence, and managing healthcare statistics. It serves not only clinical settings but also public health and epidemiology, aiming to improve the quality of care by ensuring that health records are comprehensive and accurate.

In contrast, while Current Procedural Terminology (CPT) is mainly used for coding medical procedures and services provided by healthcare professionals, and the Healthcare Common Procedure Coding System (HCPCS) includes codes for products, supplies, and certain services not included in CPT, neither focuses primarily on documenting clinical diagnoses. Diagnosis Related Groups (DRG) is a system designed primarily for billing and payment purposes within inpatient hospital settings rather than for clinical documentation. Thus, the ICD's role as a diagnostic coding system makes it the best choice for this question.