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Ristocetin Aggregation

Item Value
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.
Available Stat? No
Test code RIST
Test group vWD
Performed by Parnassus Hematology
In House Availability Run as needed Monday - Friday, day shift only.
Method Platelet aggregometry
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
Normal range
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
LOINC code 24380-8
Last Updated 3/3/2014 12:03:03 PM
Entry Number 829
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