Which code sets are used for diagnoses and procedures in outpatient coding?

• A. ICD-10-CM for diagnoses and CPT/HCPCS for procedures
• B. ICD-10-CM for diagnoses and ICD-10-PCS for procedures
• C. ICD-9-CM for diagnoses and CPT for procedures
• D. ICD-10-CM for both diagnoses and procedures

Answer: (A)

In outpatient coding, the way you separate codes is by purpose: diagnoses are captured with ICD-10-CM, while the procedures and services you perform are coded with CPT or HCPCS. CPT covers most outpatient procedures and services, while HCPCS Level II handles additional items and services not included in CPT, such as certain supplies and durable medical equipment. ICD-10-PCS, on the other hand, is used for inpatient hospital procedures, not outpatient encounters. ICD-9-CM is outdated and no longer used for new codes. So the correct pairing—ICD-10-CM for diagnoses and CPT/HCPCS for procedures—reflects current outpatient coding practice.