The assessment of platelet function is an essential component of haemostasis diagnostics and antiplatelet therapy monitoring. Classical optical aggregometry, based on measuring changes in optical density of platelet-rich plasma after the addition of platelet aggregation agonists, has long been regarded as the gold standard. However, due to technical complexity, the need for fresh samples, and operator dependence, automated systems offering higher standardization and reproducibility are increasingly implemented.
The aim of this study was to compare platelet aggregation results obtained using two automated analyzers — the CS-2500 coagulation analyzer and the Thrombomate XRA aggregometer — with those obtained using the reference method of classical optical aggregometry. The analysis was performed using five agonists: adenosine diphosphate, epinephrine, collagen, arachidonic acid, and ristocetin. Maximal platelet aggregation (%) was used as the primary endpoint.
For adenosine diphosphate and arachidonic acid, the Thrombomate XRA and the CS-2500 showed moderate to good clinical agreement with the classical method in subject classification. For adenosine diphosphate, maximal platelet aggregation tended to be slightly higher on automated systems, whereas analytical agreement for arachidonic acid was more pronounced. For epinephrine, statistically significant differences did not have clear clinical relevance and did not affect the interpretation of the aggregation response; therefore, analytical comparability could not be reliably assessed. Comparison between analyzers for collagen was limited due to non-equivalent reagent concentrations, while ristocetin, analysed exclusively in the control group, did not allow direct comparison.
Overall, the results indicate that the hypothesis of high agreement between methods was partially confirmed for adenosine diphosphate and arachidonic acid, whereas reliable assessment of comparability for the remaining agonists was limited by methodological constraints.
In conclusion, automated systems represent a promising alternative to classical optical aggregometry for agonists with demonstrated agreement. Broader clinical application and comparability across a wider range of agonists will require additional multicentre validation, harmonised reagent concentrations, and consistent quality control.
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