Donadio C, Lucchesi A, Ardini M, Giordani R
Unità di Nefrologia, Dipartimento di Medicina Interna, Università di Pisa, I-56100 Pisa, Italy.
J Pharm Biomed Anal. 2001 Mar;24(5-6):835-42. doi: 10.1016/s0731-7085(00)00550-1.
The aim of this study was to assess the diagnostic accuracy of plasma levels of three low-molecular weight proteins cystatin C, beta 2-microglobulin, and retinol-binding protein, as indicators of impairment of glomerular filtration rate in comparison with plasma creatinine.
Glomerular filtration rate (GFR) was measured in 110 patients (51 M and 59 F, aged 18--79 years); creatinine (Creat), cystatin C (Cys), beta 2-microglobulin (beta 2M), and retinol-binding protein (RBP) were determined on the same day. The correlation coefficients between the different markers and GFR were determined. Receiver-operating characteristics (ROC) analysis was performed to assess their diagnostic accuracy. Furthermore, the relationship between plasma levels of the examined markers of GFR and body weight, height, fat-free mass (FFM) and body cell mass (BCM) was determined. FFM and BCM were calculated by means of total body electrical impedance measurement.
Serum concentrations of Cys, beta 2M and RBP increase progressively with the reduction of GFR. The magnitude of the increase in blood levels of Creat and beta 2M was higher than the increase of Cys, and much more than that of RBP, in particular in patients with GFR<20 ml/min/1.73 m(2). The correlation coefficients between GFR and 1/plasma concentrations were 0.647 for Creat, 0.651 for Cys, 0.731 for beta 2M, and 0.406 for RBP. ROC analysis indicated that the accuracy of beta 2M and Cys, as indicators of different degrees of GFR impairment (<80, <60, and <40 ml/min per 1.73 m(2)), was similar to that of Creat, while the diagnostic accuracy of RBP resulted significantly lower than that of Creat for any level of GFR. In patients without renal failure (GFR>40 ml/min per 1.73 m(2)), plasma concentrations of Creat were positively correlated with body weight (P<0.01), height (P<0.01), FFM (P<0.001) and BCM (P<0.001). Serum concentrations of RBP resulted correlated with FFM (P<0.05) and BCM (P<0.05), while no correlation was found between anthropometric data and Cys and beta 2M.
Cystatin C and beta 2-microglobulin have a diagnostic accuracy very similar to that of creatinine, while retinol-binding protein is not an adequate marker of glomerular filtration.
本研究旨在评估三种低分子量蛋白（胱抑素C、β2-微球蛋白和视黄醇结合蛋白）的血浆水平作为肾小球滤过率受损指标相对于血浆肌酐的诊断准确性。
对110例患者（51例男性和59例女性，年龄18 - 79岁）进行肾小球滤过率（GFR）测量；同日测定肌酐（Creat）、胱抑素C（Cys）、β2-微球蛋白（β2M）和视黄醇结合蛋白（RBP）。确定不同标志物与GFR之间的相关系数。进行受试者操作特征（ROC）分析以评估其诊断准确性。此外，确定所检测的GFR标志物的血浆水平与体重、身高、去脂体重（FFM）和体细胞量（BCM）之间的关系。FFM和BCM通过全身电阻抗测量计算得出。
随着GFR降低，Cys、β2M和RBP的血清浓度逐渐升高。在GFR<20 ml/min/1.73 m²的患者中，Creat和β2M血水平升高的幅度高于Cys，且远高于RBP。GFR与1/血浆浓度之间的相关系数分别为：Creat为0.647，Cys为0.651，β2M为0.731，RBP为0.406。ROC分析表明，作为不同程度GFR受损（<80、<60和<40 ml/min per 1.73 m²）指标，β2M和Cys的准确性与Creat相似，而对于任何GFR水平，RBP的诊断准确性均显著低于Creat。在无肾衰竭（GFR>40 ml/min per 1.73 m²）的患者中，血浆Creat浓度与体重（P<0.01）、身高（P<0.01）、FFM（P<0.001）和BCM（P<0.001）呈正相关。RBP的血清浓度与FFM（P<0.05）和BCM（P<0.05）相关，而人体测量数据与Cys和β2M之间未发现相关性。
胱抑素C和β2-微球蛋白的诊断准确性与肌酐非常相似，而视黄醇结合蛋白不是肾小球滤过的合适标志物。
