Factor V Functional is a blood test used to evaluate the activity of Factor V, a protein involved in blood clotting. This test measures the functional activity of Factor V in the coagulation cascade. It is used to diagnose conditions where Factor V deficiency or dysfunction is suspected, such as in cases of unexplained bleeding or clotting disorders. The test can also be used to assess the presence of Factor V Leiden mutation, which increases the risk of abnormal clotting. Factor V functional testing helps determine if the protein is working properly to support normal blood clot formation.