A blood clot is a mass formed by platelets and fibrin in the blood to stop bleeding.
There are a variety of risk factors and illness that can lead to blood clot formation.
Causes of blood clots may include:
certain heart conditions,
pregnancy,
prolonged immobility,
smoking,
certain medications,
surgery, and
inherited blood clotting disorders.
Symptoms of blood clots depend on their location in the body. Some blood clots produce no symptoms until they rupture or become dislocated and travel through the circulatory system to other sites.
Signs of a blood clot depend on their location in the body. Blood clots can cause heart attack or stroke; or pain, swelling, redness and  tenderness in the area of the clot.
The diagnosis is suggested by the history and physical examination and often confirmed with an imaging test.
Treatment may require surgery, anti-coagulation medications, or a combination of the two.
Prevention of blood clots involves attention to the risk factors for vascular disease.
Serious complications can arise from blood clots, and individuals should seek medical care if they believe they may have a blood clot.