Comparison of Blood Cell Count Results Between MgSO ₄ and K2EDTA . Stability and Accuracy of Platelet Counting With MgSO ₄

Introduction We investigated the stability and accuracy of platelets with MgSO 4 and compared the results of blood counts between MgSO 4 and K2EDTA. Methods Platelet stability as a function of time was assessed on the XN Sysmex analyzer by comparing the percentage deviation to the desirable bias of the EFLM. Accuracy was determined by calculating the LoQ of platelets corresponding to a CV of 10%. Results from 250 patients were compared between K2EDTA and MgSO 4 . Results At 20°C, platelets were stable for 24 h in impedance, 10 h in fluorescence and at 4°C for 4 h in impedance, 2 h in fluorescence. This decrease is related to the formation of platelet aggregates. For platelets in fluorescence, LoQ is 4 × 10 9 /L using MgSO 4 . The results of the complete blood count did not differ between K2EDTA and MgSO 4 except for the MCV, for which the median relative bias (MRB) with respect to K2EDTA was −5.6%. For MgSO 4 platelets, the MRB is 2.9% in fluorescence and 11.9% in impedance. Conclusion The use of MgSO 4 with the XN produces results comparable to those obtained with K2EDTA, except for those related to MCV and for impedance platelets.