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Test Code
RPAG
Test Name
Ristocetin Platelet Aggregation
CPT Codes
85576
Included Tests

Ristocetin
Expected Turnaround Time
1 - 3 days
Clinical Utility

Von Willebrand disease (vWD) is the most common congenital bleeding disorder. Low levels of Ristocetin cofactor are seen in Type I, Type II, and Type III vWD.
Specimen and Container Info

Preferred Specimen Type: Plasma

Desired Specimen Volume: 2 full Light Blue Top (Sodium Citrate) tubes

Preferred Collection Container: Light Blue Top (Sodium Citrate)
Collection Instructions

All handling and collection must be in plastic containers. Platelets will adhere to glass leading to activation so glass should never be used.
Processing and Submission Instructions

Do not centrifuge or aliquot. Must remain as whole blood in original tube.
Patient Preparation
  • Patient should be fasting.
  • Drug Interferences: patient should be off all medications for 14 days prior to specimen collection. Partial drug listing includes: acetylsalicylic acid, antihistamines, chlordiazepoxide, clofibrate, cocaine, corticosteroids, diazepam, dipyridamole, furosemide, gentamicin, ibuprofen, indomethacin, marijuana, phenothiazines, phenylbutazone, propranolol, pyrimidine, sulfinpyrazone, theophylline and tricyclic anti-depressants
Transport Instructions

Transport tubes at room temperature and deliver immediately to the testing department (testing must be completed within 4 hours of collection). 
Stability Requirements

Room Temperature

Specimen must remain at room temperature. Do not chill; platelets are activated at low temperatures.
Methodology
Spectrophotometric
Reference Intervals

 81 - 97%
Performing Location
Roble Road Core Laboratory
Testing Schedule
Testing is performed by appointment only
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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