Symptoms, Diagnosis and Treatment of Excessive Blood Clotting (Hypercoagulation)

Many factors can lead to excessive blood clotting, causing limited or blocked blood flow which can be life-threatening. Signs and symptoms of excessive blood clotting depend on where the clots form.

  • A blood clot in the heart or lungs could include symptoms such as chest pain, shortness of breath and upper body discomfort in the arms, back, neck or jaw, suggesting a heart attack or pulmonary embolism (PE).
  • A blood clot in the brain could cause headaches, speech changes, paralysis (an inability to move), dizziness and trouble speaking or understanding speech, suggesting a possible stroke.
  • A blood clot in the deep veins of the leg may create symptoms such as pain, redness, warmth and swelling in the lower leg, and could suggest deep vein thrombosis (DVT) or peripheral artery disease (PAD)

If you have signs or symptoms of a heart attack, PE or stroke, call 911 right away. If you have signs or symptoms of DVT, call your health care professional right away. The cause of the blood clot needs to be found and treated as soon as possible.


If your health care professional thinks that you have excessive blood clotting, they will look for the cause of the condition by doing a physical exam.

Medical and family histories will also be reviewed in case you have a blood relative who has had:

  • Abnormal or excessive clotting.
  • A history of repeated blood clots before age 40.
  • Blood clots during pregnancy or while on birth control pills.
  • Unexplained miscarriages.
  • A history of excessive or unusual blood clots (such as in the veins in the liver or kidneys).

Blood work will also be reviewed. Initial blood tests will include a complete blood count and a platelet count. These tests measure the number of red blood cells, white blood cells and platelets in your blood. Platelets are blood cell fragments that stick together to form clots.

Your health care professional may choose to do additional blood tests if more information is needed.


While you can't prevent genetic causes of excessive blood clotting, you can take the following steps to reduce acquired risk factors:

  • Treating conditions that can lead to excessive blood clotting, such as diabetes or heart and vascular diseases like PAD.
  • Quitting smoking and losing weight, if needed.
  • Avoiding medicines that contain estrogen. Ask your health care professional about other safer options.
  • Staying active if you can. Moving your legs, flexing and stretching during long trips. This helps keep blood flowing in your calves.
  • Taking medications your health care professional may prescribe such as anticoagulants, or blood thinners, before, during and/or after surgery or medical procedures to prevent excessive blood clotting.


Excessive blood clotting is treated with medicines, but because blood clots can be dangerous, you may need emergency treatment.

The type of treatment you need depends on the size and location of the clot(s).

  • Emergency Treatment – Blood clots can damage the body, leading to serious problems, such as stroke, heart attack, kidney failure, deep vein thrombosis or pulmonary embolism. They can also cause miscarriages, stillbirths or pregnancy-related problems. Emergency treatment to prevent these problems often involves medicines called thrombolytics or "clot busters," that can quickly break up clots. These medicines can cause sudden bleeding so they're only used in life-threatening situations.
  • Routine Treatment – In a non-emergency situation, anticoagulants, or "blood thinners," are used to keep existing clots from getting larger and to prevent new clots from forming.
    • Warfarin is given in pill form. (Coumadin® is a common brand name.)
    • Heparin is given as a subcutaneous (under the skin) injection or through an IV tube. Your health care professional may treat you with both heparin and warfarin at the same time. Heparin acts quickly. Warfarin takes several days before it starts to work. Once the warfarin starts to work, the heparin is stopped.

    Direct-acting oral anticoagulants, or DOACs, are pills that may be used as an alternative to warfarin. Apixaban, betrixaban, dabigatran, rivaroxaban and edoxaban are some of the DOACs available.