Biological variability of transferrin saturation and unsaturated iron-binding capacity
Biological variability of transferrin saturation and unsaturated iron-binding capacity
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DOI：
10.1016/j.amjmed.2007.02.027
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发表时间：
2007-11-01
影响因子：
5.9
通讯作者：
Eckfeldt, John H.
中科院分区：
文献类型：
--
作者：
Adams, Paul C.;Reboussin, David M.;Eckfeldt, John H.
背景：转铁蛋白饱和度被广泛认为是血色素沉着症的首选筛查试验。不饱和铁结合能力具有类似的性能，但成本较低。然而，这两种检测的体内生物变异性可能会限制它们在常用切点检测HFE C282Y纯合子患者的能力。方法：血色病和铁超载筛查研究使用转铁蛋白饱和度、不饱和铁结合能力、铁蛋白、HFE C282Y和H63D基因分型对101,168名初级保健参与者进行铁超载筛查。转铁蛋白饱和度和不饱和铁结合容量在最初筛查时进行，当选定的参与者和对照组几个月后回来进行临床检查时再次进行。漏诊病例定义为在初次筛查或临床检查时转铁蛋白饱和度低于临界点(女性为45%，男性为50%)或不饱和铁结合能力高于临界点(女性为150mU/L，男性为125mU/L)的C282Y纯合子，或两者兼而有之，与血清铁蛋白无关。结果：在最初的筛查和临床检查中，有209例C282Y纯合子在最初筛查和临床检查时进行了转铁蛋白饱和和不饱和铁结合能力检测。在转铁蛋白饱和临界点有68例(33%)C282Y纯合子被漏掉(男性19例，女性49例；血清铁蛋白水平中位数为170u g/L；第一和第三四分位数分别为50和474mU g/L)；在不饱和铁结合能力截止点有58例(28%)被漏掉(男性20例，女性38例；血清铁蛋白中位数168mU/L；第一和第三四分位数38和454mU/L)。使用禁食样本没有任何好处。结论：转铁蛋白饱和度和不饱和铁结合能力的人内生物变异性限制了它们作为表达C282Y纯合子的初始筛查试验的有效性。(C)2007 Elsevier Inc.保留所有权利。
BACKGROUND: Transferrin saturation is widely considered the preferred screening test for hemochromatosis. Unsaturated iron-binding capacity has similar performance at lower cost. However, the withinperson biological variability of both these tests may limit their ability at commonly used cut points to detect HFE C282Y homozygous patients. METHODS: The Hemochromatosis and Iron Overload Screening Study screened 101,168 primary care participants for iron overload using transferrin saturation, unsaturated iron-binding capacity, ferritin, and HFE C282Y and H63D genotyping. Transferrin saturation and unsaturated iron-binding capacity were performed at initial screening and again when selected participants and controls returned for a clinical examination several months later. A missed case was defined as a C282Y homozygote who had transferrin saturation below the cut point (45% for women, 50% for men) or unsaturated iron-binding capacity above the cut point ( 150 mu mol/L for women, 125 mu mol/L for men) at the initial screening or the clinical examination, or both, regardless of serum ferritin. RESULTS: There were 209 C282Y previously undiagnosed homozygotes with transferrin saturation and unsaturated iron-binding capacity testing performed at the initial screening and clinical examination. Sixty-eight C282Y homozygotes (33%) would have been missed at these transferrin saturation cut points (19 men, 49 women; median serum ferritin level of 170 mu g/L; first and third quartiles, 50 and 474 mu g/ L), and 58 homozygotes (28%) would have been missed at the unsaturated iron-binding capacity cut points (20 men, 38 women; median serum ferritin level of 168 mu g/ L; first and third quartiles, 38 and 454 mu g/ L). There was no advantage to using fasting samples. CONCLUSIONS: The within-person biological variability of transferrin saturation and unsaturated iron-binding capacity limits their usefulness as an initial screening test for expressing C282Y homozygotes. (C) 2007 Elsevier Inc. All rights reserved.