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HelpTest ID RIAS Ristocetin Inhibitor Assay Screen, Plasma
Useful For
Diagnosis of inhibitors of von Willebrand factor in patients with severe (type 3) von Willebrand disease (VWD)
Diagnosis of certain acquired types of VWD
Special Instructions
Method Name
TEST CANNOT BE ORDERED WITHOUT REQUESTING PHYSICIAN'S CONSULTATION WITH MAYO CLINIC'S COAGULATION CONSULTANT.
Reporting Name
Ristocetin Inhibitor Assay Scrn, PSpecimen Type
Plasma Na CitSee Coagulation Studies in Special Instructions.
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Spin down, remove plasma, and spin plasma again.
2. Freeze specimen immediately at ≤-40° C, if possible.
Additional Information:
1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Each coagulation assay requested should have its own vial.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Clinical Information
Inhibitors of the von Willebrand factor (VWF) may occur in those patients with severe type 3 von Willebrand's disease (VWD) who have a deletion of a large part of the von Willebrand gene.
Inhibitors may also occur in patients who have no previous evidence of VWD resulting in the development of a form of acquired VWD. Only a few of the patients with acquired VWD have evidence of an inhibitor. Most patients with acquired VWD have some type of B-cell lymphocytic abnormality (hairy cell leukemia, chronic lymphocytic leukemia, non-Hodgkin's lymphoma, multiple myeloma, monoclonal gammopathy of undetermined significance, Waldenstrom's macroglobulinemia, and systemic lupus erythematosus). Other patients with acquired VWD may have some form of myeloproliferative disease. Acquired VWD rarely arises in a person who is otherwise healthy.
Most inhibitors of VWF are IgG, but occasionally IgM and IgA have been reported.
Inhibiting antibodies to VWF are measured by determining the degree of inhibition of ristocetin/VWF-induced agglutination of washed normal platelets.
Reference Values
An interpretive report will be provided.
Cautions
The absence of an inhibitor does not exclude the diagnosis of acquired von Willebrand disease. In many patients, no inhibitor is demonstrable, but some of these patients may actually have an antibody which forms antigen-antibody complexes which are rapidly removed in the circulation.
Day(s) Performed
Monday through Friday; p.m.
Report Available
1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
85245