Abstract

Many mathematical formulas containing simple red blood cell parameters have been proposed for differentiating between iron deficiency and thalassemia in patients with microcytic anemia. Approximately half of these formulas do include red cell distribution width (RDW), along with other red cell parameters. In the present study we investigated the role of RDW, expressed in relative or in absolute units in relation with the formulas’ discriminant performance. We used a database containing over 2200 subjects with microcytic anemia, for whom a final diagnosis (iron-deficiency anemia, thalassemia, both or other) was available. Performance of the discriminant formulas was assessed by Receiver Operator Curve analysis. Substitution of relative by absolute RDW resulted in statistically significant performance increase (area under the ROC curve) in 16 out of 23 formulas, predominantly due to increased specificity. Relevant performance deterioration was seen in only three formulas that had low initial performance already with the original relative RDW. For optimal differential diagnostic performance, an RDW-based formula for distinguishing thalassemia from iron-deficiency anemia in microcytic anemia should contain ‘absolute’ instead of relative RDW.

摘要

已经提出了许多包含简单红细胞参数的数学公式来区分小细胞性贫血患者的缺铁和地中海贫血。这些公式中约有一半确实包括红细胞分布宽度 (RDW) 以及其他红细胞参数。在本研究中，我们调查了 RDW 的作用，以相对或绝对单位表示，与公式的判别性能有关。我们使用了一个包含超过 2200 名小细胞性贫血受试者的数据库，对他们的最终诊断（缺铁性贫血、地中海贫血、两者或其他）是可用的。判别式的性能通过接受者操作曲线分析进行评估。在 23 个配方中的 16 个中，用绝对 RDW 代替相对值导致了统计学上显着的性能增加（ROC 曲线下面积），这主要是由于特异性增加。仅在初始相对 RDW 已经具有较低初始性能的三个公式中看到相关性能恶化。为了获得最佳的鉴别诊断性能，用于区分小细胞性贫血中的地贫和缺铁性贫血的基于 RDW 的公式应包含“绝对”而不是相对 RDW。