A blood clot is a semi-solid substance formed when blood components clump together in the blood circulation. Also, the main components of blood clots are red blood cells, white blood cells and fibrinogen. Platelets are also involved in the formation of clots. Blood clots are usually found in cases of slow blood flow, hyper viscous blood disorders, especially in veins, and in various hematocrit disorders, such as primary thrombocytosis, true erythrocytosis, etc., which tend to form clots. The formation of blood clots can cause blockage of blood vessels in the body, and in the most serious cases, the clots can be dislodged from the blood vessels, leading to life-threatening embolism.