A blood clot is a solid mass of blood that develops in one of your veins, usually in the leg. The clot, called a thrombus, blocks the flow of blood to the area of the body in which it is located. Blood clots are not always stationary; they can break away from the vein in which they are located and travel to the lungs, where thrombosis (the state of having a blood clot) can become deadly. Recognizing the symptoms, as well as using diagnostic tests, allows doctors to detect a blood clot.

Recognize the symptoms of a blood clot, and report them to your doctor. The affected body part (usually the leg) may be swollen, red in color and warm to the touch. Tenderness or an aching pain may also be a symptom of a blood clot.

Have a blood test done to check D dimer levels. The Mayo Clinic explains that D dimer is a substance in the blood that dissolves clots and may be elevated in people who have blood clots 1. This test is not always the definitive answer to whether a blood clot exists, but it can be part of the diagnostic process.

Undergo imaging testing to detect a blood clot. Magnetic imaging resonance, CT scans and ultrasounds are all used to allow doctors to literally see if a blood clot exists.

Have a vein scan, if your doctor suspects you have a blood clot. This procedure involves injecting a radioactive agent, called a tracer, into your vein. A scan is done after the tracer has had a chance to get into your bloodstream. The blood clot will be seen as a bright spot on the screen, because of the contrast of the tracer.