Coagulation Factor Tests: MedlinePlus Lab Test Information

What are Coagulation Factor Tests?

Coagulation factors are proteins in the blood that help control bleeding. You have several different coagulation factors in your blood. When you get a cut or other injury that causes bleeding, your coagulation factors work together to form a blood clot. The clot stops you from losing too much blood. This process is called the coagulation cascade.

Coagulation factor tests are blood tests that check the function of one or more of your coagulation factors. Coagulation factors are known by Roman numerals (I, II VIII, etc.) or by name (fibrinogen, prothrombin, hemophilia A, etc.). If any of your factors are missing or defective, it can lead to heavy, uncontrolled bleeding after an injury.

Other names: blood clotting factors, factor assays, factor assay by number (Factor I, Factor II, Factor VIII, etc.) or by name (fibrinogen, prothrombin, hemophilia A, hemophilia B, etc.)

What is it used for?

A coagulation factor test is used to find out if you have a problem with any of your coagulation factors. If a problem is found, you likely have a condition known as a bleeding disorder. There are different types of bleeding disorders. Bleeding disorders are very rare. The most well-known bleeding disorder is hemophilia. Hemophilia is caused when coagulation factors VIII or IX are missing or defective.

You may be tested for one or more factors at a time.

Why do I need a coagulation factor test?

You may need this test if you have a family history of bleeding disorders. Most bleeding disorders are inherited. That means it is passed down from one or both of your parents.

You may also need this test if your health care provider thinks you have a bleeding disorder that is not inherited. Although uncommon, other causes of bleeding disorders include:

In addition, you may need a coagulation factor test if you have symptoms of a bleeding disorder. These include:

  • Heavy bleeding after an injury
  • Easy bruising
  • Swelling
  • Pain and stiffness
  • An unexplained blood clot. In some bleeding disorders, the blood clots too much, rather than too little. This can be dangerous, because when a blood clot travels in your body, it can cause a heart attack, stroke, or other life-threatening conditions.

What happens during a coagulation factor test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes

Will I need to do anything to prepare for the test?

You don’t need any special preparations for a coagulation factor test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If your results show one of your coagulation factors is missing or not working right, you probably have some kind of bleeding disorder. The type of disorder depends on which factor is affected. While there is no cure for inherited bleeding disorders, there are treatments available that can manage your condition.