How do ICD-10-CM diagnosis codes differ from CPT codes?

• A. ICD-10-CM codes describe diagnoses; CPT codes describe procedures/services performed
• B. ICD-10-CM describe procedures; CPT codes describe diagnoses
• C. Both describe patient symptoms only
• D. ICD-10-CM are used for billing; CPT are used for scheduling

Answer: (B)

ICD-10-CM codes describe diagnoses, while CPT codes describe procedures or services performed. The diagnosis codes capture what condition the patient has or why the encounter occurred, providing the medical reason for care. The CPT codes specify the actual work done—codes for office visits, lab tests, imaging, surgeries, or other procedures. Both systems work together in billing: the ICD-10-CM code justifies the medical necessity, and the CPT code itemizes the service provided.

For example, a patient diagnosed with acute bronchitis might have an ICD-10-CM code for the bronchitis, while the CPT code would describe the specific service performed, such as a chest X-ray or an office evaluation. This separation helps healthcare providers communicate both the reason for care and the exact procedures carried out, which insurers use to determine reimbursement.