Question

Factor VIII Assay

Th is is a blood test that measures the activity of factor VIII. Factor VIII or factor 8 is a large protein that is important to the clotting cascade. It accelerates the activation of factor X. Factor VIII is not an enzyme, but it plays a large role in the activation of factor X. Th e factor VIII assay measures the percentage of factor VIII present in the blood. Results are represented as a percentage of factor VIII needed to from a clot. Normal levels range from 50–200%. When results are low, this test can be used to diagnose hemophilia A, Von Willebrand’s disease, and presence of factor VIII inhibitor (an antibody). For hemophilia A, levels less than 1% constitute severe hemophilia, 1–5% signifi es moderate hemophilia, and values of 6–49% are diagnostic of mild hemophilia. When values are too high, this test can be used to diagnose/as a marker for diabetes, liver disease, infl ammation, obesity, or pregnancy.

Results from Tristan’s test are listed below.

Factor VIII Assay Results – T. Hunter

Measure	Value	Normal
Factor VIII	0.27%	50–200%

Questions

6. What is factor VIII? Why would having a decreased/absent amount of factor VIII be problematic?
7. What can an abnormal factor VIII test result mean? Do any of these conditions overlap with the possible outcomes from the PTT test? Based on the combined results, what is the most likely diagnosis?

Answer 1

6.Factor VIII is known as anti-haemophillic factor.

This factor plays an important role in activating the Cascade.

Absence of this factor can be a cause of X linked recessive disorder called haemophilia A.

This factor helps in clotting of blood. If factor is absent or present in less amount then blood will not be able to clot.

7. Abnormal level of factor VII correlate with the presence of a disease called haemophilia A .

If value of PTT is also less then it will confirm that the person is suffering from haemophilia A.