Von Willebrand Factor Ristocetin Cofactor Activity (VWF:RCo)

Why This Test Matters

VWF is a protein that helps platelets stick together to form clots. When levels or function are low, bleeding can occur more easily, even from minor cuts. This test helps identify if VWF is the cause of unusual bleeding.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw blood. The process takes about 5 minutes, and you may feel a brief pinch. The test is done in a lab and results are typically ready within a few days.

Common Reasons for Testing

Doctors may order this test if you have a history of excessive bleeding, nosebleeds that don’t stop easily, heavy menstrual bleeding, or bleeding after surgeries or dental work. It’s also used to check if you’re taking medications that affect blood clotting.

What the Results Mean

Results are compared to a standard range to see if your VWF activity is within normal limits or if it’s lower than expected. Low levels may indicate a bleeding disorder, while normal levels don’t confirm a diagnosis but rule out VWF-related issues.