Reference scattergrams - Calendar 2008 special sheet

In the blood differential of the SYSMEX X-CLASS leukocytes are classified according to their content of nucleic acids (fluorescence intensity) and the complexity of their internal structure (side scatter). In the scattergram of a healthy individual the different cell populations are clearly separated: lymphocytes (LYMPH), monocytes (MONO), neutrophil and basophil granulocytes (NEUT+BASO) as well as eosinophilic granulocytes (EO). The basophil granulocytes are counted as a separate population in a different channel (WBC/BASO channel, not shown). The number of neutrophil granulocytes is calculated by subtracting the basophil granulocytes from the 'NEUT+BASO' count.

On the haematology analysers SYSMEX XE-5000, XE-2100, XT-2000i and XT-1800i also the population of immature granulocytes (IG) can be counted and displayed separately (see month 09, figure 1). For the XE-2100, XT-2000i and XT-1800i a dedicated software (IG MASTER) is required for this. On the XE-5000 this feature is integrated.

In the reticulocyte channel of the haematology analysers SYSMEX XE-5000, XE-2100 and XT-2000i all blood cells are stained with a fluorescent dye and classified by fluorescence intensity (largely correlating with the content of nucleic acids) and forward scatter. The forward scatter signal reflects the contents of a cell (for example the haemoglobin content in red blood cells) as well as the cell size. Mature erythrocytes do not contain RNA and can therefore be found in the upper left of the scattergram (RBC-O, blue). The reticulocytes contain different amounts of RNA depending on their maturity status and can be classified accordingly into 'low fluorescent reticulocytes' (LFR, purple) and ‘medium’ or 'high fluorescent reticulocytes' (MFR and HFR, red). MFR and HFR are additionally reported as the combined 'immature reticulocyte fraction' (IRF). As an immediate sign of enhanced erythropoiesis in the bone marrow an increase of the HFR population is observed. The comparably small platelets are located at the bottom of the scattergram (turquoise population). Leukocytes are usually located outside the displayed scattergram.

Moreover, the haemoglobin content of the reticulocytes (RET-H_e) can be assessed. It reflects the iron supply in the bone marrow of the patient and is therefore of great value for the differential diagnosis of anaemia, therapeutic decisions, and therapy monitoring. On the XE-2100 and the XT-2000i a dedicated software (RET MASTER) is required to measure RET-H_e. In addition, the software allows to separately count schistocytes. On the XE-5000 these features are integrated.

In addition to impedance counting of platelets the haematology analysers SYSMEX XE-5000, XE-2100 and XT-2000i provide an optical method for the measurement of platelets using a fluorescent dye. This fluorescence technology allows correct quantification of platelets also for problematic blood samples, for example with micro(erythro)cytosis, schistocytes or giant platelets. In the scattergram the platelet area is enlarged for better visibility. Immature platelets contain RNA (higher fluorescence) and are larger than mature platelets (higher forward scatter signal). On the XE-2100 the immature platelet fraction (IPF) can be assessed separately using the IPF MASTER software. On the XE-5000 this feature is integrated.