[New complete blood count parameter to evaluate iron status of haemodialysis patients]

The presence of functionnal iron deficiency during erythropoietin therapy especially in patients with chronic renal failure leads to a diagnostic problem due to the low sensitivity and specificity of the biological parameters usually used in the diagnosis of iron deficiency. However, this diagnostic appears to be essential in so far as its treatment consists in intravenous iron perfusion that allow an optimal efficiency of erythropoietin therapy. Hypochromic red blood cells and reticulocyte hemoglobin content (CHr) are two new parameters that are given by Bayer blood count analyser (H3 and ADVIA 120) that may be usefull in the diagnostic of functionnal iron deficiency. The measurement is based on optical red cell analysis by laser beam diffraction in two angles that permit to analyze content and volume. Reticulocytes are identified by dying of residual nucleic acid. Many papers have demonstrated the usefulness of these parameters in the initial take care and follow up of haemodialysis patient. It seems that these parameters are complementary and need to be analysed simultaneously; Hypochromic red blood cells having the most interesting sensibility specificity ratio but reticulocyte hemoglobin content being superior in the understanding of acute modification.