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von Willebrand Factor Collagen Binding Assay : 10924
Test CodeVWFCBQ or 10924
CPT Codes
83520
Instructions
Light Blue top 3.2% sodium citrate tube.
Transport Container
Centrifuge tube and aliquot 1 mL plasma into a standard transport tube (Min: 0.5 mL).
Transport Temperature
Frozen.
Specimen Stability
Ambient: 24 hours; Refrigerated: 24 hours; Frozen: 21 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis; Lipemia; Icteric specimen
Methodology
Enzyme Linked Immunosorbent Immunoassay (ELISA)
Setup Schedule
Monday & Wednesday
Report Available
2-7 days (From receipt at performing laboratory)
Limitations
This test was performed using a kit that has not been cleared or approved by the FDA. The analytical performance characteristics of this test have been determined by Quest Diagnostics. This test should not be used for diagnosis without confirmation by other medically established means.
Reference Range
vWf:Collagen Binding: 45-198 % normal
Ratio (CBA/vW Ag): greater than or equal to 0.50 ratio
A CBA:vWF AG ratio of <0.5 suggests a qualitative defect of von Willebrand Factor.
Ratio (CBA/vW Ag): greater than or equal to 0.50 ratio
A CBA:vWF AG ratio of <0.5 suggests a qualitative defect of von Willebrand Factor.
Clinical Significance
The Collagen Binding Activity is a surrogate assay for the measurement of von Willebrand Factor (VWF) mediated Platelet adhesion. Decreased activity (collagen bound to the A3 domain of the VWF protein) relative to the VWF antigen level, is observed with qualitative defects of VWF (type 2 disorders). The CBA assay may assist in the discrimination of type 2 disorders. In addition, there have been reports of isolated defects of CBA as a cause for a variant form of von Willebrand disease.
Performing Laboratory
Quest Diagnostics
