Comparison of platelet count results on the Sysmex XN between citrate or MgSO 4 and K2 EDTA anticoagulants

Introduction The aim of this study performed on Sysmex XN is to compare platelet values on citrate and MgSO 4 (TBX) in patients with K2EDTA‐induced platelet clusters and to identify platelet biases of these matrices compared to K2EDTA. Methods Sixty patients with K2EDTA‐induced platelet clusters were re‐sampled with K2EDTA, citrate and TBX. Platelet results were then compared, and smears were analysed for clumping. Platelet results from 120 patients without K2EDTA‐induced platelet clusters were compared between K2 EDTA, citrate, and MgSO 4 with impedance and fluorescence modes. Biases from regressions were analysed. Results Out of the 60 patients with K2EDTA‐induced platelet clusters, none showed platelet clusters with MgSO 4 whereas 50% still showed clusters with citrate. Among those without platelet clusters on citrate, the mean relative difference between (citrate‐ MgSO 4 )/MgSO 4 was −12.7% in impedance and −9.8% in fluorescence. Among the 120 patients without K2EDTA‐induced platelet clusters, in fluorescence the mean relative bias with respect to K2EDTA was −2.06% for MgSO 4 and −10.3% for Citrate. For the MgSO 4 versus K2 EDTA regressions, the maximum absolute values of the 95% CI of the relative biases at 150 × 10 9 /L (5.45%) and 450 × 10 9 /L (3.56%) were below the desirable analytical objectives of the EFLM. Conclusion In patients with K2EDTA‐induced platelet clusters, MgSO 4 is preferable to citrate. MgSO 4 provides a bias with XN in fluorescence when compared to EDTA which is within analytical tolerance.