Outpatient Facility Coding Alert

Question: On a complete bilateral duplex scan of the lower-extremity arteries, I am confused as to which diagnosis code(s) to report. In the impression, the radiologist documents bilateral increased flow velocity of the distal SFA and mildly decreased left ABI. He also documents bilateral leg pain in the indication. Which diagnoses should I code?

Utah Subscriber

Answer: First, you want to know exactly what the physician is referring to when he documents increased flow velocity and decreased left ankle-brachial index (ABI). Determination of flow velocity is simply a measurement of the speed of the intra-arterial blood blow of a given vessel. Similarly, an ABI test also gives the physician an indication of how well the patient’s blood is flowing. More specifically, it’s the calculation of the systolic blood pressure at the ankle divided by the systolic blood pressure at the arm. It’s particularly useful as a means of diagnosing peripheral artery disease (PAD).

Without the full report, including the patient’s age, it’s difficult to make a determination of whether these diagnoses are, in fact, clinically significant. However, since they are included in the impression, and not exclusively in the findings, you may consider reporting each diagnosis with a respective diagnosis code. For lack of a more specific diagnosis, you will actually be reporting both diagnoses using the same “signs and symptoms” code R09.89 (Other specified symptoms and signs involving the circulatory and respiratory systems).

Additionally, you may report bilateral leg pain as a secondary diagnosis, since the leg pain may very well be unrelated to the principal diagnosis. For bilateral leg pain you will report codes M79.604 (Pain in right leg) and M79.605 (Pain in left leg).

Coder’s note: Keep in mind that your Local Coverage Determinations (LCDs) for 93925 (Duplex scan of lower extremity arteries or arterial bypass grafts; complete bilateral study) may support one, both, or none of the included diagnoses. In the instance that neither of the diagnoses you’ve provided are deemed payable, you should submit an appeal with written documentation explaining why the procedure was medically necessary given the diagnoses provided.

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