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Test Code WBASA Platelet-Aspirin Resistance

Important Note

1.8mL Pediatric tube is not acceptable for this test.

Specimen and Container/Tube

Specimen Type: Whole Blood

Preferred Specimen: 2.7mL Blue Top Tube, 3.2% Sodium Citrate

Other Acceptable specimens: N/A

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

NOTE: Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Whole blood sample must arrive in the laboratory within three hours of specimen collection.
  • Draw two 2.7mL blue top tubes.
  • Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.
  • Do not centrifuge samples. Centrifuged samples will be rejected.
  • Send samples Room Temperature. Refrigerated or frozen samples will be rejected. 

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that have wrong ratio of blood to anticoagulant (fill volume), clotted or grossly hemolyzed.

Reference Values

 

Test

Age

Sex

Reference Range

WBASA

ALL

ALL

See Comment

 

There is no normal range but the following comment will attach to each result:

Target range for inhibition of platelet function by aspirin is <550 ARU.

Results of 550 ARU or greater indicate lack of anticipated aspirin inhibition, such as may be seen with aspirin
resistance or lack of aspirin intake.

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

85576

LOINC Codes

49011-0

Volume

Preferred Volume: Two 2.7mL Blue Top Tubes, 3.2% Sodium Citrate

 

Minimum Volume: Two 2.7 mL Blue Top Tubes, 3.2% Sodium Citrate

Specimen Stability

Storage Temperature

Stability

Room temperature

4 hours

Refrigerated

not acceptable

Frozen

not acceptable

Collection Instructions

  • Collect specimen per standard laboratory collection procedures. 
  • Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.
  • Given the critical importance of platelets remaining unactivated prior to being exposed to the ADP stimulus in the course of this assay procedure, it is vital that the venipuncture be smooth and the blood flows readily. If these criteria are not achieved, the tube should be discarded and another venipuncture performed.
  • It is also essential to follow the proper Order of Draw.

Test Components

Platelet-Aspirin Resistance

 

Clinical Indications

Measuring residual platelet function in patients on aspirin

Methodology

Platelet aggregation

Additional Information

Platelet count of > 100,000/uL is required for performance of this test.

 

3.2% sodium citrate light blue top tubes must have 9 to 1 ratio of blood to anticoagulant.

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

STAT Turnaround Time: N/A

 

Routine Turnaround Time: 4 hours

 

Testing Schedule: 7 days a week, 5:00 am to 10:30 pm

Synonyms/Keyword Search

Whole Blood Aspirin Resistance; Aspirin

Last Review Date

05/28/2024