Impact of hyperleucocytosis on erythrocytic parameters of cell blood count: management by Sysmex XN-10 RET analyzer

Extreme hyperleukocytosis can interfere with the haemoglobin measurement, red blood cell counts and the calculation of the erythrocyte indices. Current recommendations require various sample manipulations, resulting in high inter-operator variability. The aim of our study was to define an automated method on the XN-10 RET analyser to ensure the speed and accuracy of the haemogram results reported in cases of extreme hyperleukocytosis. Samples from 228 control patients without hyperleukocytosis and 81 patients with haematological malignancies with extreme hyperleukocytosis were analysed on the XN-10 RET analyser. The results of photometry haemoglobin (Hb), impedance red blood cells (RBC-I) and MCV were compared to the optical methods (Hb-O and RBC-O), as well as R-MFV. The control group allowed us to confirm that the usual methods (photometry and impedance) were correlated with the optical methods and R-MFV. Among patients with extreme hyperleukocytosis, the white blood cells (WBC) in chronic lymphocytic leukaemia (CLL) and acute lymphoblastic leukemia (ALL) groups interfered with RBC-I and MCV but not with Hb. In chronic myeloid leukaemia (CML) and acute myeloid leukemia (AML) groups, WBC interfered with Hb and not with RBC-I nor MCV. The optical methods and R-MFV have corrected the various parameters affected by interference from hyperleukocytosis. We propose a decision tree based on simple criteria for triggering optical measurements and R-MFV to quickly correct the results of parameters impacted by hyperleukocytosis.