The carotid duplex test checks blood flow in the carotid arteries. It can detect: - Blood clotting (thrombosis) - Narrowing in the arteries (stenosis) - Other causes of blockage in the carotid arteries Your doctor may order this test if: - You have had a stroke or transient ischemic attack (TIA) - You need a follow-up test because: The carotid artery was found to be narrowed in the past - You have had surgery on your carotid artery - Your doctor hears an abnormal sound called a bruit over the carotid neck arteries. This may mean the artery is narrowed. Normal results The results will tell your doctor how open or narrowed your carotid arteries are. For example, the arteries may be 10% narrowed, 50% narrowed, or 75% narrowed. A normal result means there is no problem with the blood flow in the carotid arteries. The artery is free of any blockage, narrowing, or other problem. Note: Value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.