In coding, what does ICD-10-CM coding describe?

• A. The service performed.
• B. The CPT code used for service.
• C. The insurance payer type.
• D. The diagnosis reason for the service.

Answer: (D)

ICD-10-CM coding describes the diagnosis or reason for the encounter. It captures the patient’s health problems—diseases, conditions, symptoms, or other reasons the visit happened—that justify the care provided. This is distinct from the service itself, which is described by CPT codes that name the procedures or tests performed. It also isn’t used to describe payer type. So the correct concept is that ICD-10-CM codes explain the diagnosis or reason for the service, such as the specific condition prompting the visit.