Factor VIII Assay
Factor VIII Assay
Factor VIII assay test is done to measure the activity of Factor VIII. Factor VIII is one of the proteins in the body that helps the blood to clot or coagulate. Factor VIII, along with Factor IX, is responsible for the creation of a “net” over a torn blood vessel in order to close it. However, due to the presence of an abnormal gene, some children do not have enough Factor VIII. This results in a bleeding disorder called hemophilia A.
Thus, this test is recommended to detect hemophilia A at an early stage in order to facilitate treatment and management of symptoms.
Symptoms of Hemophilia A
Prolonged bleeding after surgery
Prolonged bleeding following a dental procedure
Prolonged bleeding from minor wounds
Painful, swollen bruises
Unexplained bleeding into vital organs (e.g. Gastrointestinal tract)
Joint pain and stiffness
Heavy menstruation
Severe low back pain, usually limited to one side
Blood transfusion after a minor injury
What is the Factor VIII Assay test used for?
Diagnose and monitor treatment of hemophilia A
Find the reason for abnormal result on other clotting tests such as prothrombin time (PT) or partial thromboplastin time (PTT)
Evaluate for a bleeding disorder called Von Willebrand disease
Rule out the possibility of genetically inheriting hemophilia A from a family member
Preparation for the test
No special preparation is required for this test. Make sure that your healthcare provider is aware of all the medicines, herbs, vitamins, and supplements you may be taking.
Interpretation of results
The units of measurement for the results are often given as a percentage.
The normal range of Factor VIII assay test is 50% to 200% of the laboratory control or reference value.
Deviations from normal levels indicate the following:
Decreased factor VIII activity may indicate the following conditions:
· Hemophilia A (a bleeding disorder due to lack of blood clotting factor VIII)
· Disseminated intravascular coagulation (characterized by excessive activity of blood clotting proteins)
· Presence of a Factor VIII inhibitor (Antibody)
· Von Willebrand disease (another type of bleeding disorder)
FAQs
How is the sample collected for factor VIII assay 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 VIII assay 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 VIII deficiency test results are usually available within 4 hours from the time the sample is collected. However, this duration may vary depending on the diagnostic clinic.
How is the factor VIII assay helpful in evaluation of Van Willebrand disease?
Factor VIII circulates in the body bound to another clotting factor called Von Willebrand factor (vWF). This means that a lower amount of vWF would also mean a decreased amount of factor VIII.
What factors might affect my factor VIII assay test results?
Increased activity of Factor VIII may be due to older age, diabetes, liver disease, inflammation, pregnancy, and obesity. Taking aspirin or other NSAIDs (non-steroidal anti-inflammatory drugs) might affect the test results.
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