Advanced clinical parameters in haematology analysers
Kanchan Jeswani
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Today’s haematology analysers offer diagnostic capacities which go well beyond the scope of routine screening and so offer even greater patient safety. While routine haematology is a given in all analysers, specialty testing is possible now for platelets, immature cells of all three cell lines and body fluids. One can also individualise testing by using clinical applications to streamline further analysis and treatments, thus improving cost efficiency. As the technology advances so does the availability of new analysers with advanced clinical parameters. Few such clinical parameters are NRBC enumeration, immature granulocyte, immature platelet fraction, and reticulocyte haemoglobin, among others:
Nucleated Red Blood Cells (NRBC)
The routine determination of NRBC with every CBC replaces the manual white blood cell correction and ensures a reliable corrected white blood cell count, even at high cell concentrations. It also helps in early recognition of additional critical developments, even at low cell concentrations. It is a prognostic marker for disease severity or progression, e.g. in the case of intensive care patients or those undergoing transplantation and in neonates. NRBC enumeration gives a better assessment of ineffective erythropoiesis and severity in thalassemia or sickle cell anaemia thus aiding in optimising blood transfusion.
Immature Granulocyte (IG) count
XN 1000
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IG provides a valuable tool for physicians for concluding a diagnosis or requesting further patient investigation. With the exception of blood from neonates or pregnant women, the appearance of immature granulocytes in the peripheral blood indicates an early-stage response to infection, inflammation or other stimuli of the bone marrow. Being able to detect them quickly and reliably opens doors to new diagnostic possibilities for related disorders. The determination of circulating immature granulocytes aids in early and rapid discrimination of bacterial from viral infections particularly in children, detecting bacterial infection in neonates, and the early recognition of bacterial infection and sepsis in adults, which is of vital importance in particular for intensive care patients. The IG count of paediatric patients, especially premature neonates or neonates younger than seven days, has to be taken with care due to their immature immune systems and the greater number of immature cells in the circulating blood.
Immature Platelet Fraction – IPF
The Immature Platelet Fraction (%IPF) is a modern parameter that measures young and thereby reticulated platelets in peripheral blood. IPF levels rise as bone marrow production of platelets increases. Therefore its measurement provides an assessment of bone marrow platelet production from a peripheral blood sample, in a way similar to how a reticulocyte count provides a measure of red cell production. It is particularly useful for supporting the diagnosis of autoimmune and thrombotic thrombocytopenic purpura, and for distinguishing these from bone marrow suppression or failure. In the case of the latter, the %IPF value would be low. The %IPF can also be a sensitive measure for evaluating thrombopoietic recovery during aplastic chemotherapy. In some specialist hematology and cancer centres, for instance, %IPF is taken into consideration in platelet transfusions. Transfusions may only be considered when the %IPF values are not rising as this would indicate poor intrinsic thrombopoietic activity. Its usefulness in monitoring after chemotherapy and haematopoietic stem cell/ bone marrow transplantation has been suggested.
Cellavision DM96
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XN 3000
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Reticulocyte Hemoglobin Equivalent – RET-He
Measuring the haemoglobin content of reticulocytes, RET-He (Reticulocyte Haemoglobin Equivalent), is a way of diagnosing and monitoring iron deficiency anaemia . It can indicate whether there is enough iron available for erythropoiesis and gives an indication of the quality of erythropoiesis. It is often used for patients with nephrological disorders, Anaemia of Chronic Disease (ACD) {chronic inflammatory process, chronic infection}, Iron Deficiency Anaemia (IDA) and paediatric patients developing IDA due to the growth phase. Ret-He Indicates the trend of the current iron status. It is often used together with ferritin. A high or normal ferritin value alongwith a low RET-He value can suggest functional iron deficiency while low ferritin values alongwith low RET-He suggest a classic iron deficiency. Since ferritin is falsely increased during the acute phase of diseases, inflammation should be checked, e.g. by CRP. RET-He is used for monitoring erythropoietin (EPO) and/or IV iron therapy. If the value increases it indicates the therapy is having a positive effect.
The clinical usefulness of the Ret-He parameter has been proven and it is now an established parameter in advanced haematological analysis. ‘Reticulocyte haemoglobin content’ is recommended in nephrology guidelines such as the European Best Practice Guidelines (EBPG), National Kidney Foundation Kidney Disease Outcome Quality Initiative (NKF KDOQI).
Red cell Precursor Nucleated Red Blood Cells (NRBC) Immature Granulocytes (IG) Immature Platelet Fraction (IPF) and Reticulocyte Hemoglobin Equivalent (Ret-He) -These advanced reportable parameters of clinical significance are now available in Sysmex XN Series instruments to help doctors provide better healthcare for patients. In addition, Haematopoietic Progenitor Cells (HPC) percentage is also available in XN20 models which is helpful in haemopoietic stem cell transplantation.
Manual cell counts, smear preparation, manual staining are being replaced and giving way to automated haematology analysers with parameters and slide maker and stainer. Manual differential counts on peripheral blood and body fluids can also be automated on an analyser such as Sysmex Cellavision DM96 with pre- classification of leucocytes, pre characterisation of parts of red cell morphology, platelet estimation, verified by medical technologist and preparation of digital slides, if required.