Von Willebrand Panel

Test Code: TD_403
CPT Code(s): 85240, 85245, 85246

$149

Test Details

Alternative Name(s)

VWD Von Willebrand Disease

Test Includes

Von Willebrand Panel

Methodology

Factor VIII Activity: Electromechanical Clot Detection
VW Factor Antigen: Immunoturbidometric
VW Activity Ristocetin: latex Enhanced Immunoassay

Rejection Criteria

Room temperature samples
Refrigerated samples
Hemolysis
Clotted samples
Samples with visible red cells

Reference Range(s)

“VWB

Specimen Requirements

Preferred Specimen

Citrate (light blue top) tube

Minimum Volume

4 mL frozen plasma

Sample Stability

Unacceptable room temperature
Unacceptable refrigerated
2 weeks frozen

Transport Temperature

Critical Frozen

Collection Instructions

1. This test requires 4 frozen plasma aliquots. Fill 5 light blue top tubes as far as vacuum will allow and mix by gentle inversion five to six times. The exact ratio of 1 part sodium citrate to 9 parts blood must be maintained. Inadequate filling of the sample tube will alter this ratio and may lead to inaccurate results.
2. Patients who have hematocrit values above 55% should have the anticoagulant adjusted to maintain the 1 to 9 ratio.
3. To obtain platelet-poor plasma, immediately centrifuge sample at 1500 rcf’s for 15 minutes, then pipette the supernatant plasma and transfer to a plastic transport tube.
4. Re-centrifuge plasma in the plastic transport tube at 1500 rcf’s for 15 minutes to ensure that no red cells are present.
5. Pipette the top two-thirds of the supernatant plasma and transfer equal amounts of plasma (minimum of 1ml) into 4 separate plastic transport tubes. Clearly label tubes as citrate plasma.
6. Immediately freeze the plasma at -20 degrees C or lower for transport. All samples are Critical Frozen (CFZ).
7. When multiple tests are ordered, submit separate tubes for this test.

Alternative Specimen

N/A