Factor XII Functional
Factor XII Functional
Factor XII functional test is done to measure the amount of a protein called coagulation factor XII in a blood sample. Deficiency of this protein results in extended blood clotting (coagulation) time without any accompanying prolonged clinical bleeding tendencies. Factor XII is commonly called Hageman factor. When Factor XII comes into contact with the damaged walls of a vein, it activates coagulation factor XI. As a result of this interaction, a chain of reactions is set off which is called a coagulation cascade. This helps to form a blood clot. Factor XII is also responsible for stimulating inflammation in response to an infection, injury, or irritation.
Coagulation factor XII is made in the body with the help of the F12 gene. Mutations in the F12 gene is responsible for causing hereditary angioedema. Thus, this test may be carried out to find out if a person is suffering from hereditary angioedema (swelling under the skin).
Symptoms of hereditary angioedema
Swelling of the arms and legs
Swelling of the face
Swelling of the intestines
Swelling of the trachea (airways)
Who should get tested?
Factor XII functional test is most often used if you
Have had a recent bleeding
Want to check your risk of bleeding before undergoing a surgery
Preparation for the test
No special preparation is required for the Factor XII functional test. However, you must make sure that your healthcare provider is aware of all the medicines, herbs, vitamins, and supplements you may be taking.
Interpretation of results
The normal range of Factor XII functional test is 50% to 150% of normal clotting time, which is measured in seconds.
Deviations from normal levels indicate the following:
Longer clotting time: Indicates that you have an inherited deficiency of factor XII. It can lead to a condition called thrombosis (partial or complete blockage of blood vessel).
FAQs
How is the sample collected for factor XII functional test?
During this test, a small amount of blood is taken from a vein in your arm using a needle, which is collected in a test tube or vial. This procedure takes no longer than five minutes.
What are the risks associated with the factor XII functional test?
This test involves negligible risk. During a blood test, one may experience minor pain or bruising at the site where the needle was inserted, but most symptoms will subside quickly. Sometimes, you may get a feeling of light headedness after the test.
What is the turnaround time (TAT) for this test?
Factor XII functional test results are usually available within 24 hours from the time the sample is collected. However, this duration may vary depending on the diagnostic clinic.
What factors might affect my factor XII functional test results?
The use of heparin or any other thrombin inhibitor could alter the results of a factor XII functional test.
Does factor XII deficiency cause bleeding?
Having a deficiency of factor XII does not cause you to bleed abnormally. However, the blood might take longer to clot in a test tube.
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