CCA Medical Coding Professional Free Exam Prep

Answer: C - ICD-9 codes are necessary on a claim because they indicate the medical necessity for the service. CPT codes are used to report the procedures on a claim, and they are also used to code charges. Code linkage is what connects the procedures to the diagnoses on a claim. Code linkage also demonstrates the medical necessity of a service, but ICD-9 codes, by themselves, do not indicate a code linkage, as they have to be linked with a procedure code.