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von Willebrand Factor Antigen
Message
Performed in the Hematology Laboratory x5475, 76. Sample MUST be drawn to minimum fill line on tube.
Test Code
VWAG
CPT Codes
85246
Preferred Specimen
plasma
Minimum Volume
2.7 mL. Sample MUST be drawn to minimum fill line on tube or the sample will be rejected as QNS.
Instructions
If drawn with other coagulation assays: for up to 3 tests draw2, 2.7mL sodium citrate tubes. For 4 or more coagulation tests, draw 3, 2.7 mL sodium citrate tubes.
Transport Container
Light Blue Top (Sodium Citrate), 2.7 mL draw tubes
Transport Temperature
Room temperature
Specimen Stability
Refrigerator Stability: 4 hours
Plasma is stable for 6 months frozen at -70 degrees C.
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis, QNS, Clotted
Methodology
Turbidimetric Immunoasssay
Setup Schedule
2-3x/week, weekdays between 8-4 pm. Plasma is frozen until testing is performed.
Limitations
VWF is an acute-phase reactant and stress, pregnancy, and other situations affect its plasma concentration.
Results are not affected by hemoglobin up to 120 mg/dL, bilirubin up to 14 mg/dL, triglycerides up to 1500 mg/dL, and rheumatoid factor up to 750 IU/mL.
Results are not affected by hemoglobin up to 120 mg/dL, bilirubin up to 14 mg/dL, triglycerides up to 1500 mg/dL, and rheumatoid factor up to 750 IU/mL.
Reference Range
See interpretive data comments. Reference ranges are ABO blood group dependent.
Clinical Significance
To screen for VonWillebrand disease; differentiate VWD from hemophilia; monitor treatment
