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Factor VIII vWF Protein

Aliases

Von Willebrand Antigen Factor Assay

Useful For

von Willebrand disease (vWD)is the most common inherited bleeding disorder. Clinically, it is often characterized by mucocutaneous hemorrhages. The three principle types of vWD are:

Type 1 corresponds to a quantitative deficiency of vWF
Type 2 refers to a qualitative deficiency of vWF
Type 3 is characterized by a total absence of vWF

Patient Preparation

No special patient preparation required

Special Collection Instructions

Properly filled 9:1 ratio (blood to anticoagulant); 3.2% NaCitrate tube

Collection Method

Venous Draw; properly filled 9:1 ratio (blood to anticoagulant)

Minimum Volume

0.5 mL of plasma from a properly filled 1.8 mL or 2.7 mL NaCitrate (light blue) tube

Container

Light Blue Sodium Citrate
 

Preferred Specimen

2.7mL Lt. Blue (3.2% NaCitrate)

Acceptable Specimens

1.8 mL Lt. Blue (3.2% NaCitrate) tube

Reference or Target Ranges

46-180%

Reportable Units

% (percentage)

Critical Value

Not defined for this assay

Reasons for Rejection

Hemolysis Threshold N/A
Icterus Threshold N/A
Lipemia Threshold N/A
Interfering Subtances/Other Short draws, over draws, clotted, improperly labeled, hemolyzed, lipemic or icteric samples, samples > 4 hours from collection

Specimen Stability

Ambient Plasma – 4 hours
Refrigerated (4°C to 8°C) N/A
Frozen(-70°C to -20°C) 2 weeks@ -20°C; 1 year @ -70°C

Performance Information

Days and Time Performed Batched daily Monday-Friday unless STAT
Expected Turn Around Time Batched Monday – Friday
Stat Availability Yes
Performing Bench Coagulation
Methodology/Method Description Stago Compact – Immuno-turbidimetric determination

Special Handling

Centrifugation: 5 minutes at 5000 rpm. Plasma must be centrifuged twice
(double spun) to remove platelets. (<10,000 mm3)

Additional Information/Important Notes

After being spun down twice, separate plasma into 2 aliquot tubes and transport to University Hospital Laboratory frozen on dry ice.

CPT Codes

85246