Which option correctly pairs medical coding systems with their primary use?

• A. CPT for diagnoses; ICD 10 for procedures
• B. ICD 9 for diagnoses; CPT for procedures
• C. HCPCS for diagnoses; ICD 10 for procedures
• D. ICD 10 for diagnoses; CPT for procedures

Answer: (D)

Understanding which coding system serves diagnoses versus procedures is essential for accurate medical billing. Diagnoses are coded with ICD-10-CM, which classifies diseases, conditions, and reasons for visits. Procedures and services are coded with CPT, describing the actual actions performed, such as surgeries, tests, and professional services. This separation ensures insurers know both what condition is being treated and what care was provided, guiding payment and quality reporting.

The pairing ICD-10 for diagnoses and CPT for procedures reflects how these systems are used in practice. (Note that ICD-10-PCS is used for inpatient hospital procedures, and HCPCS Level II covers items and services not in CPT; but the main, widely used pairing for diagnoses versus procedures is ICD-10-CM for diagnoses and CPT for procedures.)