New York Subscriber
Answer: If this bilateral study did not explain why the patient is having syncope, you'll have to code the syncope, the underlying signs and symptoms, as the primary diagnosis.
Your ICD-9 manual instructs you that "if symptoms are present but a definitive diagnosis has not yet been determined, code the symptoms."
In this scenario, the patient complains of syncope (loss of consciousness). The duplex scan, an ultrasonic scan to learn the blood flow pattern in the arteries or veins, did not reveal the source of the problem. Still, you should report the complete carotid duplex using 93880 (Duplex scan of extracranial arteries; complete bilateral study).
To properly assign a diagnosis code, you need to have a more specific description of the syncope. Because the cause is still unknown, you will probably report 780.2 (Syncope and collapse), which includes cardiac and vasoconstriction syncope. But you have to code what's documented, and if there is a more specific syncope listed, code for that. For example, you could choose 337.0, which includes carotid sinus syncope.
To code for the plaque and any stenosis, determine if it's in one artery or both. If the problem is determined to be in one artery, report 433.10 (Occlusion and stenosis of precerebral arteries; carotid artery; without mention of cerebral infarction). If the problem is in both arteries, report 433.30 (... multiple and bilateral ...), and you might also want to report the underlying symptoms that caused the exam to be ordered to give the full picture.