Test ID: RIAS
Ristocetin Inhibitor Assay Screen, Plasma
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
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 and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
TEST CANNOT BE ORDERED WITHOUT REQUESTING PHYSICIAN'S CONSULTATION WITH MAYO CLINIC'S COAGULATION CONSULTANT.
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
See 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 < or =-40 degrees 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 Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretive report will be provided.
Interpretation Provides information to assist in interpretation of the test results
An interpretive report is issued. Inhibitors may also occur in patients with severe type 3 von Willebrand disease. Unlike the acquired form of the disease, these latter patients will have a history of lifelong recurrent bleeding.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Gralnick HR: von Willebrand's disease. In Disorders of Hemostasis. 2nd edition. Edited by OD Ratnoff, CD Forbes. Philadelphia, WB Saunders Company, 1991, pp 203-244
2. Shapiro SS, Siegel JE: Hemorrhagic disorders associated with circulating inhibitors. In Disorders of Hemostasis. 2nd edition. Edited by OD Ratnoff, CD Forbes. Philadelphia, WB Saunders Company, 1991, pp 245-266
Method Description Describes how the test is performed and provides a method-specific reference
Antibodies to von Willebrand factor (VWF) are detected functionally by determining the degree of inhibition of ristocetin-induced agglutination. Ristocetin is an antibiotic which produces agglutination of normal platelets in the presence of VWF. (Mannucci PM, Lombardi R, Bader R, et al: Studies of the pathophysiology of acquired von Willebrand's disease in seven patients with lymphoproliferative disorders or benign monoclonal gammopathies. Blood 1984;64:614-621)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
85245
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 9292 | Ristocetin Inhibitor Assay Scrn, P | In Process |
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