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Lab Dept:
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Coagulation
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Test Name:
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VON WILLEBRAND MULTIMERS
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General Information
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Lab Order Codes:
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VONM
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Synonyms:
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Polymers, von Willebrand Factor; von Willebrand CIEP; vWD Multimers
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CPT Codes:
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84247 – Factor VIII, von Willebrand factor, multimeric analysis
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Test Includes:
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Interpretive report of findings regarding von Willbrand related testing.
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Logistics
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Test Indications:
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Used to classify von Willebrand’s variants of type 2vWD and as an aid determining appropriate treatment.
For further interpretation of results or questions regarding Multimer analysis, please contact Pathology at (612) 813-6711. Children’s laboratory will hold specimen from von Willebrand Screen testing for one month.
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Lab Testing Sections:
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Coagulation - Sendouts
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Referred to:
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Mayo Medical Laboratories (MML Test#: 8844)
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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7 - 10 days; performed Monday and Tuesday
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Special Instructions:
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Indicate on request from when specimen is drawn from a line or a heparin lock. See Collection and Patient Preparation. Specimen should be collected prior to coagulation factor replacement therapy.
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Light Blue top (Buffered Na Citrate 3.2%) tube
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Draw Volume:
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2.7 mL blood in a 3.0 mL tube
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Processed Volume:
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1.0 mL (Minimum: 0.5 mL) plasma
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Collection:
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Routine venipuncture or line draw. Fill the tube completely. Mix thoroughly by gentle inversion. Deliver immediately to the laboratory.
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Special Processing:
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Lab Staff: Centrifuge specimen, remove plasma, spin plasma again and place 0.5 mL of platelet-poor plasma into one plastic vial. (Glass vials are not acceptable) Label appropriately and freeze specimen in von Willebrand Multimer cup in –70 degree Centrigrade freezer. Forward promptly.
Must provide results for Ristocetin Cofactor and von Willebrand Factor Antigen or if not performed, provide additional 0.5 mL of plasma in a separate plastic vial.
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Patient Preparation:
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Patient must not be receiving Coumadin® or heparin.
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Sample Rejection:
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Improper tube, Clotted samples, Underfilled tubes, Overfilled tubes, Specimens over two hours old, Mislabeled or unlabeled specimens
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Interpretive
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Reference Range:
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Interpretive report
Note: The plasma vWF multimer analysis is a qualitative visual assessment of the size spectrum and the banding pattern of vWF multimers. This test is used to identify variants of type 2 vWD that have fewer of the largest multimers, have unusually large multimers, or have qualitatively abnormal bands that indicate abnormal vWF structure.
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Critical Values:
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N/A
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Limitations:
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vWF multimer analysis is not useful if:
The following tests are normal: Factor VIII Activity Assay, Ristocetin Cofactor, von Willebrand Factor Antigen
The vWF ristocetin cofactor:vWF antigen ratio is > or = 0.7.
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Methodology:
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Agarose gel electrophoresis/infrared dye-labeled antibody detection.
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References:
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Mayo Medical Laboratories January 2010
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Harmening DH (1997) Clinical Hematology and Fundamentals of Hemostasis
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Updates:
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5/24/2010: Tubing patient specimens is no longer prohibited.
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