An ultrasound exam is the most common test used to diagnose a blood clot in the leg or arm. A CAT (or CT) scan, a sophisticated type of x-ray, is commonly used to diagnose a pulmonary embolism. A CAT scan is also the most common method used to diagnose a thrombosis in the abdomen, pelvis and head.
A thrombosis in the chest, abdomen or pelvis is sometimes discovered during a CAT scan performed for a different reason. The patient and doctor need to develop individualized treatment plans for these incidentally discovered clots.
In addition to finding the clot itself, the diagnostic evaluation sometimes involves blood tests that can help explain why the clot happened in the first place. Some of these tests look for specific genetic changes, others look for antibodies in your blood, and others test for the amount or activity of proteins that help you form and clear blood clots.
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.