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Von Willebrand Disease (VWD)
Part 2: NHLBI Diagnosis Guidelines

Laboratory Recommendations

VWD NHLBI Guidelines (2008) Initial Patient Evaluation — Laboratory1

Slide 5

May 2011

This algorithm summarizes laboratory testing recommendations for VWD (or other bleeding disorders) from the NHLBI VWD Guidelines, for initial laboratory evaluation of the patient. The upper central box in the algorithm summarizes that laboratory testing should be guided by the history and physical findings from the initial clinical evaluation.

The highlighted box on the left summarizes that laboratory evaluation should begin with the “initial hemostasis tests” (box on the left) that are ordered to screen for conditions – other than VWD – that may explain or cause bleeding or increase the risk of it, including a CBC with platelet count, and prothrombin time (PT) and partial thromboplastin time (PTT or aPTT) coagulation tests, with optional measurement of the thrombin time (TT) and/or fibrinogen level (grade C, level IV). Abnormal results of 1 or more of these tests may lead the laboratory evaluation into directions different than that for evaluating for VWD. This is a grade C level IV evidence recommendation. The highlighted box on the right summarizes that “Initial VWD assays” may be obtained subsequently or simultaneously with the “initial hemostasis tests”, especially if the mucocutaneous bleeding history assessment is relatively strong. The initial VWD assays include 3 tests: 1) VWF antigen, abbreviated VWF:Ag, 2) VWF ristocetin cofactor activity abbreviated as shown, and 3) Factor VIII coagulant activity.

Initial Patient Evaluation — Laboratory1


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