von Willebrand Factor Activity

vWF:RCo Ristocetin Cofactor Activity vWF:GPIbR
Sodium citrate (blue top) %

About this test

Functional assay measuring vWF ability to agglutinate platelets in the presence of ristocetin. Disproportionately low compared to vWF:Ag in type 2 vWD variants.

Reference Ranges

Sex Age Range Notes
All ≥ 18 yrs 50 – 200 Adult

Clinical Interpretation

Low / Decreased
Low activity — vWD type 1 (proportionally low), type 2 (disproportionately low vs antigen), type 3 (absent).
Specimen
Sodium citrate (blue top)
Reporting Unit
%

⚠ Clinical Note
Reference ranges are indicative. Always interpret results in the context of the individual patient and local laboratory reference intervals, which may vary.