Contribution of the new XN‐1000 parameters NEUT‐RI and NEUT‐WY for managing patients with immature granulocytes

Sir, Haemogram is the most commonly prescribed examination by clinicians to laboratories in France for both diagnostic purposes and patient follow-up. Haematology disorder suspicions in particular are often based on an initial cell blood count and differential. New automated haematology analysers let one quantify immature granulocytes (IG) in number (IG#) or in percentage (IG%). Occurrence of IG in peripheral blood is a frequent criterion for slide review and could appear not only in case of haematological malignant disease [myeloproliferative syndrome, myelodysplastic syndrome (MDS) or chronic myelomonocytic leukaemia] but also in infectious (septic) or noninfectious reactive (inflammatory) conditions. In most of cases, IG and IG% in blood have an infectious origin without any cytological contribution to an improvement in results but contribute significantly to an increase in manual review rates in daily practice. In Caen University hospital, about 10% of samples show an IG count above 2% and 3% of samples are over 5%. A persistently increased IG count (>10%) in the case of infection is considered as a grave criteria for sepsis [1]. When IG appear or disappear, they provide real-time information but no indication of the evaluation of the patient’s status. It would be interesting to offer the possibility of relating the occurrence of IG to infectious or noninfectious conditions and ‘anticipating IG% variation’ to efficiently supply the clinician with information regarding the patient’s outcome. The aim of our study was to investigate the potential contribution of research parameters provided by XN1000 (Sysmex CorporationTM, Hyogo, Japan), Neutrophil Granularity Intensity (NEUT-GI), Neutrophil Reactive Intensity (NEUT-RI) and width on y-axis (NEUT-WY) in enhancing the laboratory process for both management of IG count and clinical contribution. Neutrophil Granularity Intensity, expressed in side scatter intensity, is derived from the NEUT-X parameter already used by the Sysmex XE series analysers. Neutrophil Granularity Intensity is the mean value of high angle diffraction and represents the complexity of the neutrophils (nucleus lobularity, granulations) and has proven to be related to dysplasia of neutrophils on XE-2100 [2, 3] and to be independent of the IG% value. Combined with other parameters, it is useful for detecting MDS syndromes or chronic myelomonocytic leukaemia (CMML) at diagnosis and is an effective contribution to both laboratory clinical contribution and workflow improvement. Neutrophil Reactive Intensity, expressed in fluorescence intensity, is representative of the mean fluorescence of the neutrophils and can therefore be related to the activation or immaturity of the population. It is derived from NEUT-Y on XE instruments and few data are available relating the value of this parameter to infection disease/sepsis management [4, 5]. NEUT-WY represents the width of the neutrophil scattergram in the WDF channel on the fluorescence axis. This parameter is calculated according to distribution width as it represents the range of the distribution in fluorescence of the major population, excluding outliers below 20% peak height in the distribution curve. It is then representative of heterogeneous fluorescence signal in this population related to either band cells or activated neutrophils. First, we studied a large group of patients to determine the normal ranges of these new structural parameters. Then, we analysed the potential contribution of these parameters on interpreting IG count in blood samples collected from patients without any haematological disease. All blood samples were collected in K2-EDTA tubes and analysed routinely on properly controlled XN-1000 analysers. The IG compartment measured by the XN-1000 analyser included promyelocytes, myelocytes and metamyelocytes. To define the normal ranges of structural parameters, we analysed 3082 strictly normal samples in terms of the quantitative values documented by the ‘Groupe Francophone d’H ematologie Cellulaire’ (GFHC) [6] and without any qualitative flag issued by the analyser. The mean values obtained for NEUT-GI, NEUT-RI and NEUT-WY were 151.045 4.13 (1 SD), 45.43 2.796 (1 SD) and