von Willebrand factor Ag

Keywords: von Willebrand factor antigen, VWF:Ag

Specimen:

4.5 mL blood added to 0.5 mL citrate.

Method:

ELISA, electroimmunoassay, immunoradiometric assay or EIA: level of VWF:Ag in test plasma expressed as a percentage of that in pooled, normal plasma.

Reference Interval:

Refer to laboratory. Generally 50-200% of the level in pooled normal plasma, sometimes expressed as 0.5-2.0 U/mL.

Application:

Investigation of a possible bleeding disorder: diagnosis of von Willebrand disease (VWD) and its variant forms.

Detection, in association with Factor VIII assay, of carriers of haemophilia A.

Interpretation:

See von Willebrand disease testing, Ristocetin cofactor, Collagen binding assay.

Reference:

Favaloro EJ. Clin Haematol. 2001; 14: 299-319.

Marder VJ et al. Thromb Haemost. 1985; 54: 871-872.