Which statement about ICD-10 and CPT coding is true?

• A. CPT codes diagnose conditions
• B. ICD-10 codes diagnose conditions and CPT codes describe procedures for billing
• C. ICD-10 codes replace CPT codes
• D. CPT and ICD-10 codes serve the same purpose

Answer: (B)

ICD-10-CM codes identify diagnoses and conditions, providing the medical reason for the encounter. CPT codes, on the other hand, describe the procedures and services performed, which are used for billing and reimbursement. That separation is what makes this statement true: ICD-10 codes diagnose conditions, CPT codes describe procedures for billing. CPT codes don't diagnose conditions, and ICD-10-CM codes don't describe procedures. In practice, the two systems work together—the diagnosis codes justify the medical necessity, while the procedure codes reflect what was done. For a concrete example, a patient diagnosed with pneumonia would receive an ICD-10-CM code for pneumonia, and the CPT codes would cover the visit, imaging, tests, and any procedures performed.