| Ordering Code | 8447 |
|---|---|
| Test Name | von Willebrand Factor Activity |
| Alias | vWF Activity |
| Preferred Specimen | Plasma |
| Preferred Container | Citrate, 3.2% (Lt Blue) |
| Other Specimen/Container | Whole Blood in Citrate, 3.2% (Lt Blue) if testing is done within 4 hours. |
| Optimum Volume | Plasma: 1 mL Whole Blood: Entire Tube |
| Collection Instructions | Draw full tube Mix tube well. |
| Handling Instructions | Double centrifuge to produce platelet-poor plasma, avoid the WBC/platelet buffy layer, separate and freeze at -20 deg C immediately. Do NOT thaw once specimen is frozen. Thaw frozen specimens at 37C. Testing must be done within 2 hours of thawing. |
| Transport Requirements | Preferred method of transport is frozen plasma. |
| Specimen Stability | Ambient: 4 Hours Refrigerated: Not Stable Frozen: 2 Weeks Plasma |
| Rejection Criteria | Clotted, Contaminated, Hemolyzed, Improperly filled or underfilled tube, Collected in the wrong anticoagulant, Mislabeled, Specimen older than stability limits |
| Avail. Stat | NO |
| Analytic Time | Up to 3 Days |
| Methodology | Immuno-turbidimetric |
Reference range(s)
The reference ranges listed below are valid on this date of October 8, 2025.
| Component | Age | Male Norm | Male Critical Low | Male Critical High | Female Norm | Female Critical High | Female Critical Low | Units | Add'l info |
|---|---|---|---|---|---|---|---|---|---|
| von Willebrand Factor Activity | ALL | 40.3-163.4 | 40.3-163.4 | % |
