High MW vWF

Single-analyte tests

• High Molecular Weight Kininogen (HMWK) 117359

  Plasma · Fasting not stated · Turnaround 4 - 8 days

  Method and collection

  Method

  Clot-based

  Preparation

  Do not draw from an arm with a heparin lock or heparinized catheter.

  Collection

  Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.50 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.51,52 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples, except when using a winged blood collection device (i.e., "butterfly"), in which case a discard tube should be used.53,54 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge and carefully remove the plasma using a plastic transfer pipette, being careful not to disturb the cells. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested . Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.

  Reference notes

  71–165%

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Panels that include this biomarker

• Contact Factor Evaluation Profile 117250

  4 analytes · Plasma · Fasting not stated · Turnaround 5 - 8 days

  Method and collection

  Method

  See individual tests.

  Collection

  Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.21 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.22,23 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples, except when using a winged blood collection device (i.e., "butterfly"), in which case a discard tube should be used.24,25 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge and carefully remove the plasma using a plastic transfer pipette, being careful not to disturb the cells. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested .

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• von Willebrand Factor (vWF) Multimers 117245

  4 analytes · Plasma · Fasting not stated · Turnaround 5 - 7 days

  Method and collection

  Method

  The Sebia Hydragel™ assay employs an agarose gel for the separation of plasma proteins according to their molecular weight. The electrophoretic separation is carried out after sample treatment with an anionic detergent. This treatment disrupts the three-dimensional structure of the plasma VWF, allowing for the electrophoretic separation of the multimers based on their molecular weight. The system can reveal the loss or retention of HMWM and also intermediate MWM (IMWM) and thus serve as an aid in the characterization of the majority of VWD cases, for example, distinguishing samples with loss of HMWM (and potentially IMWM) (being type 2A, 2B or PT-VWD) from samples without loss of HMWM and/or IMWM (being type 1, 2M, 2N VWD or normal samples), from samples without VWF (i.e., type 3 VWD).1,2 von Willebrand Factor Antigen and Activity levels are measured in order to determine dilution needed for the multimer analysis and as an aid in interpretation of multimer pattern.

  Collection

  Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.24 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.25,26 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set, a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.27,28 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.

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