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Test Code LAB331 von Willebrand Activity

Methodology

Immunoturbidimetric Assay

Reflex Information              

If  result is abnormal, vWF GPIbM Activity will be performed at Versiti Wisconsin, Inc. at an additional charge.  CPT code 85397

Literature References:      

HemosIL von Willebrand Factor Activity package insert issued 04/2010, Instrumentation Laboratory.

                                  

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Specimen Requirements

Specimen Requirement (Tube/Container)      

Specimen Type: Plasma

Container/Tube: Light-blue top (citrate)

Specimen Volume: 1 Full tube

Specimen Minimum Volume: 1 full tube

Collection Instructions:

  1. Draw a discard blue top tube prior to drawing a light-blue top (citrated) tube if using a Winged Infusion Set.  Discard tube should be under filled and discarded.
  2. Clotted blood or an insufficient specimen is not acceptable.
  3. Avoid phlebotomy techniques which cause hemolysis and heparin contamination.
  4. Follow nursing policy on volume of blood to discard prior to collecting blood from indwelling heparinized catheters.

Analyte Stability:
4 hours at 18° C to 24° C.

Platelet-free plasma can be frozen at -20 for transport on dry ice up to 72 hours
or stored 6 months at -70° C.


Additional Information: If the patient is a hospital patient and the hematocrit is >55%, call Barnes-Jewish Hematology Laboratory at 314-362-5203 for instructions.

Reference Values

50-180 %     

    

Literature References:

Raneem O. Salem, Elizabeth M. Van Cott, A New Automated Screening Assay for the Diagnosis of von Willebrand Disease, Am J Clin Pathology 2007; 127:730-735                                           

Test Classification and CPT Coding

85245

Specimen Transport Temperature

Ambient Yes/Refrigerate NO/Frozen Yes

 

Day(s) Test Set Up

 

Monday, Wednesday, and Friday

Cut-off time: 0700

Turnaround Time:

STAT: not available

Routine: results available the day of testing

Barnes-Jewish Hospital Additional Information:

Laboratory Processing Instructions        

For BJH Laboratory Use Only

Analyte Stability:

4 hours at 18° C to 24° C.

Platelet-free plasma can be frozen at -20 for transport on dry ice up to 72 hours
or stored 6 months at -70° C.

Laboratory Processing Instructions:

Test performed in BJH Core Lab.

LOINC Code Information

Name                                LOINC Code

vWF Activity                      68324-3