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Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Clopidogrel anti-platelet effect: an evaluation by optical aggregometry, impedance aggregometry, and the platelet
Anna Dyszkiewicz-Korpanty1, Horatiu Olteanu, Eugene P Frenkel
1Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
Platelets
|September 14, 2007
Summary
Whole blood aggregometry is more sensitive than optical methods for assessing clopidogrel
Area of Science:
- Pharmacology
- Hematology
- Clinical Chemistry
Background:
- Clopidogrel's antiplatelet effect can be suboptimal in 4-30% of patients.
- Optical aggregometry in platelet-rich plasma (PRP) is the traditional method for assessing clopidogrel response.
- Red blood cells influence platelet function and ADP levels, potentially affecting aggregation assays.
Purpose of the Study:
- To compare the sensitivity of whole blood impedance aggregometry versus optical aggregometry in PRP for detecting clopidogrel's antiplatelet effects.
- To evaluate the performance of the Platelet Function Analyzer (PFA-100) in assessing clopidogrel response.
Main Methods:
- 17 healthy subjects underwent platelet function testing at baseline and after 10 days of clopidogrel (75 mg/day).
- Evaluated ADP- and collagen-induced aggregation using optical and impedance methods.
- Assessed whole blood closure time using the PFA-100 with ADP and epinephrine cartridges.
Main Results:
- Whole blood impedance aggregometry showed significantly greater inhibition of ADP-induced platelet aggregation (71% ± 34%) compared to optical aggregometry (34% ± 23%) (p=0.0002).
- The PFA-100 assay prolonged ADP closure time above the reference interval in only 29% of subjects, indicating low sensitivity.
- Whole blood aggregation detected clopidogrel's effect more effectively, likely due to the inclusion of red blood cells.
Conclusions:
- Whole blood impedance aggregometry is more sensitive than traditional optical aggregometry in detecting clopidogrel's antiplatelet effect.
- The PFA-100 assay is not sufficiently sensitive to detect clopidogrel's impact on platelet function in this context.
- Assessing platelet function in whole blood offers a more physiologically relevant method for monitoring clopidogrel therapy.
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