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

Laboratory Recommendations

VWD NHLBI Guidelines (2008) Subsequent Patient Evaluation—Laboratory1

Slide 8

May 2011

The highlighted box at the bottom summarizes that, if 1 or more of the initial VWD assay test results are abnormal (ie, decreased), referral of the patient or blood samples should be considered for selected specialized studies, based on the pattern of initial VWD test results, together with information from the clinical assessment and reflecting clinical experience. Not all of the listed tests would be performed for additional VWD evaluation, however the first 3 are frequently performed (repeating initial VWD assays, evaluating the ratio of VWF ristocetin cofactor to VWF antigen, and performing VWF multimer evaluation). Some of the recommended specialized VWD tests may be performed reflexively in laboratories able to do so, using the same plasma samples from the patient, whereas repeating blood sample collection may be indicated in other cases or for certain of the specialized tests. Obtaining expert consultation or advice from a hemostasis specialist may be helpful for planning specialized VWD testing, including selecting tests and interpreting results. The first 6 tests listed reflect grade B recommendations, whereas the last 2 are primarily research-related tests with evolving clinical applications (ie, platelet VWF studies, and DNA sequencing of the VWF gene).

The first 5 tests or procedures are discussed in the next slide.

Subsequent Patient Evaluation—Laboratory1


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