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Platelet Aggregation – RIPA (Ristocetin-induced)

Justification

Type 2B von Willebrand Disease (VWD) and platelet-type VWD are bleeding disorders caused by increased affinity between von Willebrand Factor (VWF) and glycoprotein Iba (GPIba) on the surface of platelets. In type 2B VWD, the mutation resulting in increased binding occurs in the gene encoding VWF. In platelet-type VWD, the mutation occurs in the gene encoding GPIba . An increased platelet aggregation response to low concentrations of Ristocetin are consistent with a Type 2B or platelet-type von Willebrand Disease.

STAT: < 24 hours (M-F)

Light Transmittance Aggregometry (LTA)

Draw Tube: Blue Top

Sample Type: Citrated Whole Blood

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED Citrated Whole Blood Four tubes, 3mL each (or equivalent volume) For pediatric minimum, please call (800) 566-3462. Room Temperature: 4 hours
By appointment only - must arrive at lab within 2 hours of draw
ALTERNATIVE - - - -
REJECTION CRITERIA Samples received more than 2 hours after draw
SPECIAL INSTRUCTIONS See Draw Guide By appointment only

General Information

METHODOLOGY Light Transmittance Aggregometry (LTA)
STAT TAT < 24 hours (M-F)
STAT TAT Performance > 90% of results released in 24 hours
ROUTINE TAT < 24 hours (M-F)
ALTERNATIVE NAMES Ristocetin-induced Platelet Aggregation, RIPA
DESCRIPTION Platelet aggregation is measured in response to high and low concentrations of Ristocetin by light transmittance aggregometry (LTA). Increased response to low concentrations of Ristocetin are consistent with Type 2B or platelet-type von Willebrand Disease.
LIMITATIONS Hemolytic, Icteric, and Lipemic samples
NORMAL RANGE Interpretation: Normal
ASSOCIATED TESTING -
REFERENCES -
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED -

Test Codes

ORDER CODE P3304
CPT CODE 85576x4
LOINC CODE 33550-5, 79130-1, 5998-0, 13592-1, 21027-8