Which test is commonly used to assess a hemophiliac?

The activated partial thromboplastin time (APTT) is the most relevant test for assessing hemophilia because it specifically evaluates the intrinsic pathway of the coagulation cascade, which is where deficiencies in clotting factors associated with hemophilia occur. Hemophilia primarily affects factors VIII and IX, which are integral to the intrinsic pathway; therefore, monitoring APTT allows healthcare providers to understand how well the blood is clotting in individuals with this disorder. A prolonged APTT indicates a potential deficiency or dysfunction of these factors, which confirms the likelihood of hemophilia.

In contrast, prothrombin time (PT) assesses the extrinsic pathway and is more relevant for conditions affecting those factors, such as vitamin K deficiency or liver dysfunction, but not primarily for hemophilia. The platelet count indicates the number of platelets present in the blood and does not directly assess the clotting factors involved in hemophilia. Finally, activated clotting time (ACT) is typically used in specific clinical scenarios such as monitoring anticoagulation therapy during procedures, rather than for diagnosing or assessing hemophilia. Thus, APTT is the preferred choice for evaluating coagulation issues in hemophiliac patients.