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| Primary Name |
Ristocetin Cofactor |
| Synonym |
Von Willebrand factor activity |
| Synonym |
-- |
| Contraction |
VWF Activity |
| Contraction |
VWF:RCo |
| Contraction |
-- |
| UAB Procedure Number |
2500350 |
| CPT Code |
85245 |
| Specimen |
Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill. |
| Specimen Management |
Centrifuge blue-stopper tube within one (1) hour of collection, separate plasma and test or quick-freeze at -70°C. |
| Specimen Accepted |
Daily including weekends |
| Times Available |
0730-1600 |
| Test Performed |
Monday-Friday |
| Available Stat? |
Pathologist approval required. |
| Description |
The ristocetin cofactor test is the primary assay used to diagnose von Willebrand disease as it measures plasma von Willebrand factor activity. |
| Reference Interval |
50-166% |
| Critical Value |
-- |
| Therapeutic Range |
-- |
| Follow-up Test |
*The ristocetin cofactor test is usually performed together with the von Willebrand factor antigen and the factor VIII activity assay, forming the von Willebrand disease profile.
* When type 2B von Willebrand disease is suspected, the ristocetin response curve is suggested.
*When type 2A or 2B von Willebrand disease is suspected, the von Willebrand factor multimer assay is suggested. |
| Associated With |
Bleeding disorders |
| Associated With |
Von Willebrand disease |
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