Primary Care Coding Alert

Question: A 65-year-old patient is on Coumadin for his cardiac arrhythmia. He came in for a follow-up evaluation. The physician performed a prothrombin time test to see how quickly the patient's blood was clotting. How should we code this visit?

Colorado Subscriber

Answer: First, you should use the appropriate-level E/M office visit code (99211-99215). Also use 85610 (Prothrombin time) for the test. For the diagnosis, report V58.61 (Encounter for other and unspecified procedures and aftercare; long-term [current] drug use; long-term [current] use of anticoagulants) to indicate to the payer that the physician is following the patient's blood condition regularly. You should also code the cardiac arrhythmia as a secondary diagnosis (e.g., 427.9, Cardiac dysrhythmias; cardiac dysrhythmia, unspecified).

When performing a lab test, it is important that the diagnosis code reflect the medical necessity. If you think there is a chance that Medicare will not pay for the lab test due to lack of medical necessity, have patients sign an advance beneficiary notice (ABN) before the visit so they are responsible for payment if the claim is denied.