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If you have additional questions regarding this test, please call: 415-353-1667
|Clinical Questions||Does my patient have von Willebrand disease? If so, which type?|
|Approval req'd?||Test run by appoinment only. Contact Hematology at x3-1747.|
|Performed by||Parnassus Hematology|
|In House Availability||Run as needed Monday - Friday, day shift only.|
|Patient Preparation||Patient should be rested, fasting since midnight, and no smoking before blood collection. No caffeine and no alcohol for 48 hours prior to testing. Take only medication as directed by physician before testing.|
|Collection Instructions||By appointment only, contact Hematology at x3-1747
Samples are only collected by Hematology techs.
|Container type||Blue top tube (x6)|
|Amount to Collect||20 mL blood|
|Sample type||Citrated whole blood|
|Preferred volume||20 mL blood|
|Min. Volume||17 mL blood|
|Synonyms||Ristocetin activity; von Willebrand; RIPA; Ristocetin induced platelet aggregation|
|Turn around times||1-3 days|
|Additional information||An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.
A platelet count is required for the performance of this assay and will be ordered and separately charged.
Test RIST, Ristocetin Aggregation, is a platelet aggregation using only ristocetin at both normal and low dose concentrations.No other agonists are used.
Platelets in plasma from vWD Type-2B patients have a heightened response to "low dose" ristocetin.
In Type 2B VWD, the mutant vWf has an abnormally enhanced tendency to bind to platelets.
|CPT coding||85576 x2|
|Last Updated||1/27/2015 2:49:23 PM|