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Test Directory


Ristocetin Platelet Aggregation (High and Low)

Order Name RIPA AGG
Test Number: 1501930
Revision Date 01/08/2021
Test Name Methodology LOINC Code
Platelet Aggregation, Ristocetin High
Aggregation 5998-0 
Platelet Aggregation, Ristocetin Low
Platelet Count for Agglutination
Flow cytometry 777-3 
Pathology Report
Specimen Specimen Volume (min) Specimen Type Specimen Container Transport Environment
Preferred See Instructions Whole Blood Sodium Citrate 3.2% (Blue Top) and EDTA (Lavender Top) Room Temperature

COLLECTIONS and TESTING MUST BE SCHEDULED with the lab at Ascension St. John Coagulation Department!
Please call the coagulation department to make testing arrangements:
(918) 744-2500 x15513.

If OFF-SITE collection is Authorized by the Coagulations Department, the specimens must reach Ascension St. John RML Lab within 1 hour of collection and before 1pm. If you cannot arrange for specimens to arrive in this time frame, Do Not Collect Specimen!

Patient Must be fasting for at least 8 hours before collection.

Collect Both:
- Four (2.7mL) 3.2% Sodium Citrate - Blue top tubes
- One (4.5mL) EDTA - Lavender top tubes

Keep specimens whole blood (Do Not Spin) - Keep specimen at Room Temperature!

Patient should refrain from aspirin, phenylbutazone, phenothiazines or antihistamines for 10 days prior to the test. Patient should have PLT count Greater than 75,000 for accuracy.
Testing Schedule Mon - Fri (7am - 1pm) 
Expected TAT 1 Day  
Clinical Use Platelet aggregation studies are done to evaluate platelet function. This is a specialized test and would normally be performed in patients with some indicator of a qualitative platelet disorder. 
CPT Code(s) 85576x2, 8557626
Lab Section Coagulation