Kalantar-Zadeh K, Höffken B, Wünsch H, Fink H, Kleiner M, Luft F C
Department of Internal Medicine, Staten Island University Hospital, NY, USA.
Am J Kidney Dis. 1995 Aug;26(2):292-9. doi: 10.1016/0272-6386(95)90649-5.
The purpose of this study was to evaluate the sensitivity and specificity of laboratory methods in the diagnosis of posterythropoietin-era, iron-deficient, chronic renal failure patients. The patient population comprised 25 anemic (hemoglobin < 11 g/dL) patients with creatinine greater than 3 mg/dL; 20 were dialysis patients, two were transplant patients, and three patients had renal failure from other causes. Criteria for study inclusion were as follows: bone marrow iron was the reference standard and was graded 0 to +4, ranging from absent to diffuse homogeneous iron staining; serum ferritin concentration and serum transferrin saturation were tested in terms of sensitivity and specificity. The reference standard indicated that iron deficiency existed in 40% of patients. Neither serum ferritin nor transferrin saturation were completely adequate diagnostic tools. Serum ferritin levels less than 200 ng/dL were 100% specific for the diagnosis but only 41% sensitive. Transferrin saturation of less than 20% was 88% sensitive, but only 63% specific. By excluding patients with hypoproteinemia (transferrin values of < 150 mg/dL), the sensitivity of the test increased to 100% and the specificity to 80%. We conclude that transferrin saturation is an adequate screening tool in anemic chronic renal failure patients, provided that hypoproteinemia is not present. By determining both the serum ferritin concentration and the transferrin saturation, a high sensitivity and specificity can be achieved, even in patients with hypoproteinemia. Furthermore, we believe that on this basis, iron therapy in patients with renal insufficiency can be improved.
本研究的目的是评估实验室方法在诊断促红细胞生成素时代后缺铁性慢性肾衰竭患者中的敏感性和特异性。患者群体包括25名贫血（血红蛋白<11 g/dL）且肌酐大于3 mg/dL的患者；其中20名是透析患者，2名是移植患者，3名患者因其他原因导致肾衰竭。研究纳入标准如下：骨髓铁作为参考标准，分级为0至+4，范围从无铁染色到弥漫均匀的铁染色；检测血清铁蛋白浓度和血清转铁蛋白饱和度的敏感性和特异性。参考标准表明40%的患者存在缺铁。血清铁蛋白和转铁蛋白饱和度都不是完全足够的诊断工具。血清铁蛋白水平低于200 ng/dL对诊断的特异性为100%，但敏感性仅为41%。转铁蛋白饱和度低于20%的敏感性为88%，但特异性仅为63%。通过排除低蛋白血症患者（转铁蛋白值<150 mg/dL），检测的敏感性提高到100%，特异性提高到80%。我们得出结论，转铁蛋白饱和度是贫血慢性肾衰竭患者的一种足够的筛查工具，前提是不存在低蛋白血症。通过同时测定血清铁蛋白浓度和转铁蛋白饱和度，即使在低蛋白血症患者中也能实现高敏感性和特异性。此外，我们认为在此基础上，可以改善肾功能不全患者的铁治疗。
