Laboratory algorithm

• We recommend laboratory testing only with a clinical suspicion of a bleeding disorder.

• We recommend as first step to exclude VWD and coagulation deficiencies by screening laboratory tests.

Initial screening tests

• Full blood count, consider including an estimate of platelet volume (mean platelet volume; Consider immature platelet fraction in patients with thrombocytopenia)

• Activated partial thromboplastin time (APTT)

• Prothrombin Time (PT) or international normalized ratio (INR)

• Thrombin Time (TT)

• Clauss fibrinogen activity

• Von Willebrand factor (VWF) antigen, VWF activity, factor VIII (FVIII) and IX (FIX) activity

If the initial coagulation factor assays are normal, it may be considered to exclude the extremely rare

• Factor XIII, V, or XI deficiency