Activated Protein C Resistance (APCR) is a blood test that evaluates how effectively activated protein C can regulate blood clotting. Reduced sensitivity to activated protein C may indicate an increased tendency to form abnormal blood clots, often associated with Factor V Leiden. The test is needed to investigate unexplained or recurrent venous thrombosis, assess inherited clotting disorders, and help evaluate individuals with a suspected predisposition to abnormal blood clot formation.
It is a condition in which the blood-clotting system responds inadequately to activated protein C, potentially allowing clotting activity to continue for longer than normal.
Factor V Leiden is an inherited genetic change in the factor V clotting protein that can make it resistant to activated protein C and increase the risk of venous thrombosis.
Not necessarily. APCR can suggest resistance to activated protein C, but genetic testing for the Factor V Leiden mutation may be needed to confirm the specific cause.
It may be considered when a blood clot occurs at a young age, is recurrent, occurs without an obvious trigger, or there is a personal or family history suggesting inherited thrombophilia.
An abnormal result indicates reduced sensitivity to activated protein C. Further testing may be required to determine whether Factor V Leiden or another factor is responsible.