Test Background This procedure can be used for the investigation of inhibitors against specific coagulation factors, usually factors VIII and IX. These inhibitors arise in fewer than 10 % of haemophiliacs. Specific antibodies against coagulation factors vary in specificity and reaction kinetics; some are directed against the active site of the clotting factor molecule, leading to the more severe clinical problems, others against the phospholipid or cofactor binding regions.
Clinical Indications Patients with inherited haemophilia where there is failure to respond appropriately to administered coagulation factor replacement Patients who have unexplained prolongation of their prothrombin or activated partial thromboplastin time (APPT), which may suggest an underlying acquired inhibitor to a clotting factor, eg. acquired haemophilia, where an antibody is against the FVIII coagulation protein
Sample Required 3 x 4.5 mL sodium citrate (pale blue top)
Turnaround Time 14 days
Notes Special handling: avoid prolonged stasis during venepuncture. Sample must be received by lab within 2 hours of collection. Please note: samples will be rejected if underfilled, clotted or haemolysed, or if they come from patients receiving anticoagulant therapy. Similarly, sampling is inappropriate within 4 weeks post-childbirth, or during an acute phase inflammatory response.