Collagen-binding Activity (CBA / vWF Collagen Binding Activity) Profile

Screen for the presence of type II von Willebrand disease in plasma⁶.

vWF is an acute phase reactant protein and levels may be increased transiently into the normal range in some individuals with mild vWD following adrenergic stimulation or in response to certain drug therapies such as DDAVP or estrogen.

This procedure may be considered by Medicare and other carriers as investigational and, therefore, may not be payable as a covered benefit for patients.

The collagen binding assay (CBA) can aid in the differentiation between von Willebrand disease type I and type II when used in conjunction with the vWF antigen assay. This assay evaluates the ability of high molecular weight multimers present in the patient's sample to bind collagen which is coated on the microtiter plates. The amount of vWF bound is measured using peroxidase-conjugated antibodies to human vWF. Following the addition of substrate, color intensity is proportional to the high molecular weight multimers present in the sample. Results are expressed as percent collagen-binding activity and also as a ratio of percent collagen-binding activity to total vWF antigen. The CBA activity correlates more closely with vWF function and bleeding problems than ELISA for vWF antigen levels.

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