Overview
What is Factor-VIII?
Factor-VIII Assay Test is a type of blood test that is performed to diagnose and treat Hemophilia A. Factor VIII is present in all human bodies, but if the concentration is higher than normal, it may indicate the presence of Hemophilia A.
This test is performed to diagnose Hemophilia A. The same test may be performed during the treatment for the disease and also after it has been cured completely. This test can aid the doctors in knowing how well the treatment is working.
- How is this test performed?
This test is performed on a blood sample. A syringe with a fine needle is used to withdraw blood from a blood vessel in your arm. The healthcare provider will tie an elastic band around your arm to make the blood vessels swell with blood. This makes it easier to withdraw blood. You may be asked to tightly clench your fist. Once the veins are clearly visible, the area is cleaned with an antiseptic solution and then the needle is inserted into the blood vessel to collect the sample. You will feel a tiny pinprick during the procedure. Blood sample once collected will then be sent to the laboratory.
- Is there any risk associated with this test?
There is no risk associated with the test. However, since this test involves a needle prick to withdraw the blood sample, in very rare cases, a patient may experience increased bleeding, hematoma formation (blood collection under the skin), bruising or infection at the site of needle prick.
- Is there any preparation required before the test?
Inform the doctor about the medications you may be taking. No other specific preparations are usually required before this test.
- Are there other blood types apart from the ABO and Rh blood types?
Apart from the ABO and Rh blood groups, human blood has been classified into more than 200 blood types under different grouping systems. These are less commonly used and are called minor or rare blood groups. These are not detected by the blood grouping test but are detected only by an RBC screening test for different antigens.
- Which blood groups are known as universal donors and recipients?
Individuals of blood type O Rh- are known as universal donors since they do not have antigens A, B, or Rh on their RBCs, which allows their blood to be transfused safely without any reaction from the recipient. Individuals with blood type AB Rh+ are called universal recipients since they recognize all A, B, and Rh antigens as self and do not produce antibodies against any of these, allowing them to safely receive all blood types without a harmful reaction
Hemolytic Disease of Fetus and Newborn or HDFN is a condition where the blood type of the fetus is incompatible with the blood type of the mother. The most severe reactions typically occur due to Rh incompatibility, where antibodies are produced in the Rh negative mother against Rh positive fetus. These antibodies cross the placenta and react with the RBC of the fetus, causing HDFN.
Interpretations
If the Factor VIII concentration is between 55 and 200%, it indicates that the person has tested negative for Hemophilia A. However, if the concentration is higher, the results are considered positive for Hemophilia A.
