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von Willebrand Screen
Test CodeCPT Codes
85240, 85245, 85246, 85730
Includes
Factor VIII Activity, Clotting
von Willebrand Factor Antigen
Ristocetin Cofactor
Preferred Specimen
Minimum Volume
Instructions
Note: Storage of whole blood at refrigerated temperatures prior to processing may lead to cryoprecipitate formation and falsely low Factor VIII and von Willebrand Factor studies.
Transport Temperature
Specimen Stability
Refrigerated: Unacceptable
Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Methodology
See individual tests
Setup Schedule
Reference Range
Clinical Significance
This test may be used for initial evaluation of individuals with clinical suspicion of von Willebrand disease (VWD).
von Willebrand factor (VWF) is a blood coagulation protein that has 2 functions: (1) mediating platelet adhesion to the injured endothelium and (2) acting as a protective carrier protein for coagulation factor VIII. Deficiency of VWF causes VWD, the most common inherited bleeding disorder that affects approximately 1 in 1,000 individuals at the primary care level [1]. VWD is classified into type 1 (quantitative deficiency of VWF), type 2 (qualitative deficiency of VWF), and type 3 (total absence of VWF). Different types of VWD are further categorized into subtypes, identification of which is important to inform prognosis and treatment decisions.
Three tests are recommended for initial diagnosis of VWD [2]: VWF antigen, platelet-dependent VWF activity (eg, ristocetin cofactor), and factor VIII activity. Additional tests may be needed to further identify the subtype of VWD.
Test results of acquired von Willebrand syndrome (AVWS) may be similar to those of congenital VWD [1, 2]. However, patients with AVWS do not have a family history of bleeding or a personal life-long history of bleeding. Conditions associated with AVWS include lymphoproliferative disorders, monoclonal gammopathy of undetermined significance, Wilms tumor expressing GPIb, myeloproliferative disorders, aortic stenosis, ventricular assist devices, and hypothyroidism.
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. James PD, et al. Blood Adv. 2021;5(1):280-300.
2. Higgins RA, et al. Platelets and van Willebrand factor. In: Rifai R, et al, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier Inc; 2022.
Performing Laboratory
Quest Diagnostics Nichols Institute |
14225 Newbrook Drive |
Chantilly, VA 20153 |