Von Willebrand disease laboratory findings

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Laboratory Findings

The diagnosis of von Willebrand’s disease (VWD) begins with a relevant personal or family history of mucocutaneous bleeding. When VWD is suspected, the first level of testing comprises measurements of the the following: [1]

  • VWF antigen (VWF:Ag) level,
  • VWF–ristocetin cofactor activity [VWF:RCo] as a measure of platelet-binding activity of VWF, and
    • The VWF:RCo assay may be replaced by newer assays that measure the binding of VWF to a recombinant wild-type GPIb fragment with the use of ristocetin or the spontaneous binding of VWF to a gain-of-function recombinant mutant GPIb fragment.
  • Factor VIII activity (FVIII:C).

When the results of all first-level tests are normal, VWD is ruled out; because of biologic variability, however, the tests should be repeated if values are at the low end of the normal range or if VWD is strongly suspected. [1] If these first-level tests reveal definitive abnormalities, a diagnosis of VWD can be made; if the results are not conclusive, second-level tests are required. VWD can be subtyped on the basis of these second-level tests. A rare platelet defect due to a gain-of-function mutation in the GPIbα receptor, known as platelet-type VWD, has a phenotype similar to that of type 2B VWD; the two disorders can be distinguished with the use of genetic testing. RIPA denotes ristocetin-induced platelet aggregation, VWF:FVIIIB VWF–FVIII binding activity, and VWFpp VWF propeptide. Persons with a bleeding tendency who have VWF levels between 30 and 50 IU per deciliter (the lower limit of the normal range) are classified as having “low VWF” or “possible type 1 disease” but are not classified as having definitive VWD. [1]

When von Willebrand factor antigen is undetectable (or the level is <5 IU per deciliter, according to the latest disease classification), type 3 von Willebrand’s disease is diagnosed[2]


  • A platelet aggregation assay will show an abnormal response to ristocetin with normal responses to the other agonists used. A platelet function assay (PFA) will give an abnormal collagen/adrenaline closure time and in most cases (but not all) a normal collagen/ADP time. Type 2N can only be diagnosed by performing a "factor VIII binding" assay. Detection of vWD is complicated by vWF being an acute phase reactant with levels rising in infection, pregnancy and stress.

Other tests performed in any patient with bleeding problems are:

Other coagulation factor assays may be performed depending on the results of a coagulation screen.

  • Patients with Von Willebrand disease will typically display a normal prothrombin time and a variable prolongation of partial thromboplastin time.

References

  1. 1.0 1.1 1.2 Sanders YV, Groeneveld D, Meijer K, Fijnvandraat K, Cnossen MH, van der Bom JG, Coppens M, de Meris J, Laros-van Gorkom BA, Mauser-Bunschoten EP, Leebeek FW, Eikenboom J (2015). "von Willebrand factor propeptide and the phenotypic classification of von Willebrand disease". Blood. 125 (19): 3006–13. doi:10.1182/blood-2014-09-603241. PMID 25673639.
  2. Sadler JE, Budde U, Eikenboom JC, Favaloro EJ, Hill FG, Holmberg L, Ingerslev J, Lee CA, Lillicrap D, Mannucci PM, Mazurier C, Meyer D, Nichols WL, Nishino M, Peake IR, Rodeghiero F, Schneppenheim R, Ruggeri ZM, Srivastava A, Montgomery RR, Federici AB (2006). "Update on the pathophysiology and classification of von Willebrand disease: a report of the Subcommittee on von Willebrand Factor". J. Thromb. Haemost. 4 (10): 2103–14. doi:10.1111/j.1538-7836.2006.02146.x. PMID 16889557.

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