Abstract
Background: Platelet light transmission aggregometry (LTA) can be performed using a Sysmex CS series, an automatic measuring device. However, it is observed that the sample of platelet-rich plasma (PRP) moves to the left and stays for a long time in the device owing to the multisample processing. We investigated the time course of platelet activation following platelet-rich plasma preparations on CS-2000i. Methods: PRP samples from normal healthy donors were allowed to stand from 0 to 180 min after preparation. The platelet activity of these samples with or without mixing was assessed by LTA using CS-2000i. Final concentrations of 0.5 and 2 μM ADP and 0.5 and 2 mg/μL collagen were used. We also determined the platelet count at the supernatant or lower part of the sample. Results and Conclusions: The results showed that the time course of platelet aggregation was not affected within 120 min. However, the platelet activation was attenuated when the sample was weakly stimulated with ADP after 30–90 min of platelet preparation, or was stirred before the measurement after allowing the sample to stand for a long time. Although the platelet count at the lower part of the sample was approximately 10% higher than that at the supernatant, no considerable effect on platelet activation was observed. Therefore, it was suggested that leaving the sample for a long time does not affect the results of this assay under the given conditions. However, it is necessary to pay attention to the timing of the assay after PRP preparation in the determination of platelet activation.
