Abstract:

Objective To investigate whether the depolymerization effect of optical platelet（PLT） count on ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia（EDTA-PTCR） applicable to reversible PLT aggregation that occurs immediately after anticoagulant blood collection. Methods A total of 201 venous blood samples collected from December 2021 to August 2022 at the outpatient and emergency departments of Tongren Hospital of Shanghai Jiao Tong University School of Medicine，Nanjing Hospital Affiliated to Nanjing Medical University，Guangzhou First Hospital Affiliated to Guangzhou Medical University and Xuzhou Children's Hospital. PLT counting was performed at 0，5，15 and 30 min after blood collection using CDR mode. Blood smear preparation and staining were performed at the above time points for partial samples. PLT aggregation was evaluated at the both sides，the tail and the edge of blood smears. Results Comparing with impedance PLT count at 30 min，the mean deviations at 0，5 and 15 min were 6.92%，3.28% and 1.65%，respectively. Comparing with optical PLT counts at 30 min，the mean deviations at 0，5 and 15 min were 0.76%，0.35% and 0.03%，respectively. PLT counts were higher in optical method compared to impedance method at 0，5 and 15 min after blood collection（P<0.001）. No statistical significance was found between the 2 methods at 30 min after blood collection（P=0.686）. Conclusions The mean deviation of impedance PLT count at 0 min after blood collection is >5% caused by reversible PLT aggregation，which could be corrected by optical method.

Key words: Platelet, Optical platelet counting method, Impedance platelet counting method, Platelet aggregation, Pseudothrombocytopenia