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4459: Ristocetin Cofactor (4459X) Print View
vWf: Ristocetin Co-Factor AGGL  42 - 200  % normal 

PRIMARY
1 Plasma Citrated 1 (0.5) mL   Frozen - 30 Day(s)/Room Temperature - 6 Hour(s)  
ALTERNATE

von Willebrand Disease is the most common hereditary bleeding disorder. von Willebrand Factor is necessary for platelet adhesion to injured endothelium. Ristocetin Cofactor is useful in assesing binding of von Willebrand Factor to platelet factor GP1b. When combined with other tests, results are useful in categorizing the type of von Willebrand Disease.

Platelet-poor plasma: Centrifuge light blue-top tube for 15 minutes
at approximately 1500 g within 60 minutes of collection.
Using a plastic pipette, remove plasma, taking care to
avoid the WBC/platelet buffy layer and place into a plastic vial.
Centrifuge a second time and transfer platelet-poor plasma into a new
plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze
immediately and ship on dry ice. Note: Storage of whole blood at
refrigerated temperatures prior to processing may lead to
cryoprecipitate formation and falsely low Factor VIII and von
Willebrand Factor studies.
Setup Schedule
Monday-Friday

Reported (Analytical Time)
Next day

CPT Code
85245

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Notes
Reject Criteria: Hemolysis, Lipemia, Thawed plasma, Received room temperatue, Received refrigerated.






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