Factor VIII activity
Factor VIII activity, The activity level of Factor VIII, a vital protein involved in blood clotting, is measured by the Factor VIII activity test, a blood test. Haemophilia A, von Willebrand disease, and other clotting disorders are among the illnesses for which this test is frequently used to diagnose and treat abnormal bleeding and clotting.
Purpose of the Factor VIII Activity Test
- Haemophilia A Diagnosis: A Factor VIII deficiency is the underlying cause of the hereditary condition known as hemophilia A. The test validates the diagnosis and aids in estimating the degree of Factor VIII activity.
- Evaluation of the von Willebrand disease Because of its function in maintaining Factor VIII stability, this disorder may lead to decreased Factor VIII activity—the test aids in both condition monitoring and diagnosis.
- Assessment of Unexplained Bleeding: The test determines whether a Factor VIII deficiency is a contributing factor in cases of unexplained or excessive bleeding in patients.
- Treatment Monitoring: The test assists patients undergoing Factor VIII replacement therapy in tracking the efficacy of their treatment and modifying dosages as necessary.
- Pre-Surgical Assessment: The test is performed before surgery, particularly in patients with a known bleeding issue, to ensure that Factor VIII levels are sufficient to stop excessive bleeding.
How the Exam Is Conducted:
Blood Sample Collection: Usually from the arm, a vein is used to take a blood sample.
Laboratory Analysis: The sample is examined in a laboratory to determine Factor VIII’s activity level. This entails titrating the blood with particular reagents and timing the coagulation process.
Test Findings:
Normal Range: The normal range for Factor VIII activity is between 50% and 150% of baseline levels.
Low Factor VIII Activity: Deficits resulting from hemophilia A, von Willebrand disease, or acquired diseases are indicated by levels less than 50%.
High Factor VIII Activity: Conditions like inflammation, pregnancy, and some types of cancer can be associated with levels above 150%. Additionally, it can make thrombosis (clot formation) more likely.
Analysis of the Findings:
Haemophilia A: Factor VIII activity levels below 1% indicate severe hemophilia A, values between 1% and 5% indicate moderate hemophilia, and levels between 6% and 50% suggest mild hemophilia A.
Von Willebrand Disease: This illness can be diagnosed with reduced Factor VIII activity in addition to other specialized diagnostics.
Variables Impacting Test Outcomes:
- Medication: A few medications may have an impact on Factor VIII levels.
- Stress and Illness: Stress or an acute medical condition can momentarily increase Factor VIII activity.
- Sample Handling: Accurate results depend on the blood sample being handled and processed properly.
Monitoring and Intervention:
If the Factor VIII activity test results in a deficiency, other examinations and testing are usually conducted to identify the underlying cause and the best course of action. Possible course of treatment options include:
- Factor VIII Replacement Therapy: Synthetic or plasma-derived Factor VIII concentrates are given to patients with hemophilia A.
- Desmopressin (DDAVP): This drug can help raise Factor VIII levels in people with mild hemophilia A or some forms of von Willebrand disease.
- Handling of Underlying Conditions: It’s important to treat the underlying cause (liver disease, autoimmune, etc.) of acquired deficits.