Certified Billing and Coding Specialist CBCS-B Practice Test 2026 - Free Billing and Coding Practice Questions and Study Guide

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 ICD-9-CM is outdated and no longer used for new codes.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.