Abstract

Unbound iron binding capacity (UIBC) is more accurate than total iron binding capacity (TIBC) and percent transferrin saturation in diagnosing empty iron stores. It is unknown whether UIBC is more or less accurate than soluble transferrin receptor (sTFR). We obtained public-use data from the U.S. National Health and Nutrition Examination Survey (NHANES) 2005-2006 to compare the accuray of UIBC and sTFR in diagnosing empty iron stores in 2337 women aged 12–49 years. We grouped the women according to CRP less than 5 mg/L and pregnancy (four groups) and used three definitions of empty iron stores: Serum ferritin less than 10, 15, and 20 µg/L. Receiver operating characteristic (ROC) curve analysis was used to estimate the diagnostic accuracy. UIBC showed a better diagnostic accuracy than sTFR in all groups and definitions of empty iron stores, except in nonpregnant women with CRP at least 5 mg/L when empty iron stores were defined as ferritin less than 10 and 15 µg/L. Two differences reached statistical significance: In nonpregnant women without inflammation the area under the ROC curve for UIBC was 0.830 compared to 0.793 for sTFR (p = .007) when empty iron stores were defined as ferritin less than 20 µg/L. The corresponding figures for pregnant women without inflammation were 0.843 for UIBC and 0.739 for sTFR (p = .003). In conclusion, UIBC is a more accurate test than sTFR in diagnosing empty iron stores in women without inflammation.

摘要

在诊断空铁储存时，未结合铁结合力 (UIBC) 比总铁结合力 (TIBC) 和转铁蛋白饱和度百分比更准确。尚不清楚 UIBC 是否比可溶性转铁蛋白受体 (sTFR) 更准确或更不准确。我们从 2005-2006 年美国国家健康和营养检查调查 (NHANES) 中获得了公共使用数据，以比较 UIBC 和 sTFR 在诊断 2337 名 12-49 岁女性空铁库存方面的准确性。我们根据 CRP 低于 5 mg/L 和怀孕（四组）对女性进行分组，并使用空铁储备的三种定义：血清铁蛋白低于 10、15 和 20 µg/L。接受者操作特征（ROC）曲线分析用于估计诊断准确性。UIBC 在所有组和空铁储存定义中显示出比 sTFR 更好的诊断准确性，除了在 CRP 至少为 5 mg/L 的非妊娠女性中，当空铁储存被定义为铁蛋白低于 10 和 15 µg/L 时。两个差异达到了统计学显着性：在没有炎症的非妊娠女性中，UIBC 的 ROC 曲线下面积为 0.830，而 sTFR 为 0.793。p  = .007) 当空铁储存被定义为铁蛋白低于 20 µg/L 时。无炎症孕妇的相应数字对于 UIBC 为 0.843，对于 sTFR 为 0.739 ( p  = .003)。总之，在诊断无炎症女性的空铁储备方面，UIBC 是比 sTFR 更准确的测试。