Factor VIII activity is a blood test that measures the level of a protein called factor VIII, which plays a crucial role in blood clotting. This test is often used to diagnose hemophilia A, a bleeding disorder caused by a deficiency in factor VIII. It can also be used to monitor the effectiveness of treatment for hemophilia A or to evaluate other bleeding disorders. Normal factor VIII activity levels range from 50% to 150%. Levels below 50% may indicate hemophilia A, while levels above 150% may suggest other underlying conditions.

THE VON WILLEBRAND FACTOR ANTIGEN (VWF:AG) TEST MEASURES THE AMOUNT OF VON WILLEBRAND FACTOR (VWF) PROTEIN IN THE BLOOD. 1 VWF IS ESSENTIAL FOR BLOOD CLOTTING, AS IT HELPS PLATELETS STICK TOGETHER AND FORM A CLOT AT THE SITE OF AN INJURY. 2 THIS TEST IS USED TO DIAGNOSE VON WILLEBRAND DISEASE, A BLEEDING DISORDER CAUSED BY A DEFICIENCY OR DYSFUNCTION OF VWF. 3 IT CAN ALSO BE USED TO MONITOR THE EFFECTIVENESS OF TREATMENT FOR THIS CONDITION AND TO EVALUATE BLEEDING TENDENCIES IN INDIVIDUALS WITH OTHER MEDICAL CONDITIONS. 4