Bovy Christophe, Gothot André, Delanaye Pierre, Warling Xavier, Krzesinski Jean-Marie, Beguin Yves
Department of Nephrology, Laboratory of Hematology, CHU Sart-Tilman, B35, B-4000 Liège, Belgium.
Nephrol Dial Transplant. 2007 Apr;22(4):1156-62. doi: 10.1093/ndt/gfl765. Epub 2007 Jan 20.
The percentage of hypochromic red blood cells (RBCs) (%HYPO) has been demonstrated as the best predictor of response to iron loading in haemodialysis patients treated with recombinant human erythropoietin (rHuEPO). However, we have previously shown that this parameter is positively influenced by erythropoietic activity since reticulocytes are considered hypochromic by cell counters. New cell counters are able to determine cell volume and haemoglobin (Hb) concentration separately on reticulocytes and mature erythrocytes. The aim of this study was to assess the sensitivity and specificity of mature erythrocyte parameters in detecting functional iron deficiency (FID).
A total of 32 stable chronic haemodialysis patients in the maintenance phase of rHuEPO therapy were included. Classical parameters of iron monitoring and mature erythrocyte parameters were measured after a 4-week iron-free period. Patients were classified as responders (R) or non-responders (NR) to an iron load of 100 mg iron sucrose at each dialysis session for 4 weeks, according to whether their Hb increased by >1 g/dl at the end of iron loading.
Twelve patients were identified as responders. Receiver operating characteristic (ROC) curve analysis demonstrated %HYPO and its corresponding parameter on mature erythrocyte, %HYPOm, as the best predictors of FID. The other parameters were ordered as follows: tranferrin saturation (TSAT), ferritin (FRT), mature RBC Hb content (CHm), mean corpuscular Hb concentration (MCHC), percentage of mature erythrocytes with a low CHm (%lowCHm), mean content in Hb (MCH) and reticulocyte Hb content CHr. Comparing the parameters at different cut-offs, the best sensitivity, specificity and efficiency were demonstrated for %HYPOm> 6%.
The best efficiency to predict FID was found for %HYPOm> 6%. The predictive value of %HYPO was quite similar. The clinical impact of %HYPOm in iron monitoring should also be tested in the induction phase of rHuEPO treatment because of its independence from erythropoietic activity.
低色素红细胞（RBC）百分比（%HYPO）已被证明是接受重组人促红细胞生成素（rHuEPO）治疗的血液透析患者铁负荷反应的最佳预测指标。然而，我们之前已经表明，由于细胞计数器将网织红细胞视为低色素细胞，该参数受到红细胞生成活性的正向影响。新型细胞计数器能够分别测定网织红细胞和成熟红细胞的细胞体积和血红蛋白（Hb）浓度。本研究的目的是评估成熟红细胞参数在检测功能性缺铁（FID）方面的敏感性和特异性。
纳入32例处于rHuEPO治疗维持阶段的稳定慢性血液透析患者。在4周无铁期后测量铁监测的经典参数和成熟红细胞参数。根据患者在4周内每次透析时静脉注射100mg蔗糖铁后血红蛋白是否升高>1g/dl，将患者分为铁负荷反应者（R）或无反应者（NR）。
12例患者被确定为反应者。受试者操作特征（ROC）曲线分析表明，%HYPO及其在成熟红细胞上的相应参数%HYPOm是FID的最佳预测指标。其他参数的排序如下：转铁蛋白饱和度（TSAT）、铁蛋白（FRT）、成熟RBC Hb含量（CHm）、平均红细胞Hb浓度（MCHC）、低CHm成熟红细胞百分比（%lowCHm）、Hb平均含量（MCH）和网织红细胞Hb含量CHr。比较不同临界值下的参数，%HYPOm>6%时显示出最佳的敏感性、特异性和有效性。
发现%HYPOm>6%对预测FID的效率最佳。%HYPO的预测价值非常相似。由于%HYPOm独立于红细胞生成活性，其在铁监测中的临床意义也应在rHuEPO治疗的诱导期进行测试。
