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HelpTest Code VWF Von Willebrand Factor Assay
Synonyms/Keywords
Ristocetin Cofactor, von Willebrand Factor Activity
Specimen Requirements
| Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|
| *Platelet Poor Plasma | 3.2% Citrated Blue Top Tube (BTT) | 0.75 mL | 0.75 mL | 0.5 mL |
Collection/Processing Instructions
One 0.75 mL citrated Blue Top Tube (BTT) plasma aliquot. (If more than one coagulation test is ordered, a separate aliquot is needed for each test.)
- Collect in Citrated Blue Top Tube (BTT)
- Citrate anticoagulant must be adjusted for HCT >55%
- Tube must be at least 90% full
- Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma | Frozen | 6 months |
Rejection Criteria
| Clotted or Hemolyzed |
|---|
| Contamination with IV or Hickman Line fluids |
| Specimens that thaw during storage or transport |
Test Information
Patients with blood group O have approximately 25% lower levels of von Willebrand factor and antigen. If the ABO blood group is not known on the patient, ABO blood typing is recommended to properly interpret the results of laboratory tests for von Willebrand's disease.
Contact Marshfield Labs 24 Hour Services at 800-222-5835, ext. 16383 with pre-operative requests.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield | 38-170% |
Marshfield Labs Performing Department
Marshfield Labs Hematology
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday and Thursday | Less than 2 hours | Glycoprotein 1b receptor, immunoturbidimetric assay/ACL TOP 550 |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 85245 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 85245 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Centricity | Von Willebrand Factor Assay |
| Cerner | Von Willebrand Factor Assay |
| COM | Von Will Factor Assay |