Urrechaga Eloísa
Hematology Laboratory, Hospital Galdakao-Usansolo, Galdakao, Vizcaya, Spain.
Clin Chem Lab Med. 2008;46(12):1752-8. doi: 10.1515/CCLM.2008.355.
% Microcytic and % hypochromic red cells show an inverse trend in beta thalassemia trait and in iron deficiency anemia (IDA). The aim of this study was to assess the discriminant value of % microcytic/% hypochromic ratio, as can be obtained from the Advia 2120 (Siemens) analyzer, in the differential diagnosis of microcytic anemia, compared to the conventional England and Fraser, Green and King, Mentzer, Ricerca, Shine and Lal and Srivastava indices.
Receiver operating characteristic (ROC) curves, sensitivity, specificity and Youden index of indices were calculated for a set of 148 IDA patients and 170 beta thalassemia carriers.
The Green and King index showed the best area under the curve (AUC, 0.962), with a Youden index of 80.9%; the % microcytic/% hypochromic ratio ranked second (AUC 0.943), with a Youden index of 76.3% and a sensitivity of 99.2%.
This index, with high sensitivity for beta thalassemia screening, can be a useful tool in the differential diagnosis of microcytic anemia, so samples can be chosen for HbA(2) analysis, to confirm the presumptive diagnosis of the disease. As specificity is 77.1%, we assume it will be 22.9% for false positives, but these samples will have HbA(2) values within the reference range, for correct diagnosis.
在β地中海贫血特征和缺铁性贫血（IDA）中，小细胞和低色素红细胞呈现相反趋势。本研究的目的是评估从Advia 2120（西门子）分析仪获得的小细胞/低色素比率在小细胞贫血鉴别诊断中的判别价值，与传统的英格兰和弗雷泽、格林和金、门泽尔、里塞尔卡、沙恩和拉尔以及斯里瓦斯塔瓦指数进行比较。
计算了一组148例IDA患者和170例β地中海贫血携带者的指标的受试者工作特征（ROC）曲线、敏感性、特异性和约登指数。
格林和金指数显示曲线下面积最大（AUC，0.962），约登指数为80.9%；小细胞/低色素比率排名第二（AUC 0.943），约登指数为76.3%，敏感性为99.2%。
该指数对β地中海贫血筛查具有高敏感性，可作为小细胞贫血鉴别诊断的有用工具，因此可以选择样本进行HbA(2)分析，以确认疾病的初步诊断。由于特异性为77.1%，我们认为假阳性率为22.9%，但这些样本的HbA(2)值将在参考范围内，以进行正确诊断。
