Factor assays can be performed where a coagulation factor deficiency is suspected in order to identify abnormal levels of specific coagulations factors. Factor assays are performed using methods based upon the PT or APTT, which are specific for factors II, V, VII and X or factors VIII, IX, XI and XII, respectively. Factor XIII is performed by a chromogenic method and FVIII can also be assayed by a chromogenic method as an alternative to the APTT based method. Abnormally low results may be significant in a bleeding diathesis, although factor XII deficiency is not associated with an increased risk of bleeding. Factor assays can also be used to monitor known haemophiliacs receiving factor concentrate.
Clinical Indications By approval of Consultant Haematologist
Investigation of a suspected coagulation factor deficiency Family history of haemophilia Monitoring pre and post factor concentrate administration