Giampietro O, Clerico A, Miccoli R, Cruschelli L, Di Palma L, Navalesi R
Cattedra di Malattie del Ricambio, University of Pisa, Italy.
Diabetes Res. 1988 May;8(1):39-43.
While proteinuria detectable by dip-sticks is the hallmark of overt diabetic nephropathy, urinary albumin excretion (UAE) above normal but Albustix-negative (so-called microalbuminuria) is the main characteristic of the preproteinuric phase of the diabetic renal disease. Reliable measurement of UAE requires very sensitive and accurate methods, such as radioimmunoassay (RIA), which, however, are not suitable for routine UAE analysis. The Coomassie Brilliant Blue dye binding method has been suggested to be a simple and economical way of indirectly measuring albuminuria in diabetic patients. In the present paper, we compared the chemico-clinical characteristics of a RIA method with those of the Coomassie dye binding method, in order to verify if it is really possible to calculate albuminuria from proteinuria (and vice versa) by a simple linear regression equation, as previously suggested. The RIA has shown a better sensitivity and accuracy in comparison to the dye binding method. Our study suggests that there is not a linear relationship between proteinuria and albuminuria in diabetic patients. Indeed, the ratio between the total proteinuria, as measured with the dye method, and the albuminuria, as measured by a specific and sensitive RIA, varies greatly in diabetic patients with or without glomerular nephropathy. While the dye binding method appears the best procedure for the assay of total microproteinuria, since it is precise, cheap and feasible, the RIA, due to its high sensitivity and specificity, is more suitable for early and accurate detection of microalbuminuria, as well for the close follow-up of subjects at risk of developing overt diabetic nephropathy.
虽然用试纸条可检测出的蛋白尿是显性糖尿病肾病的标志，但尿白蛋白排泄量（UAE）高于正常水平但Albustix试纸检测呈阴性（即所谓的微量白蛋白尿）是糖尿病肾病蛋白尿前期的主要特征。可靠地测量UAE需要非常灵敏和准确的方法，如放射免疫测定法（RIA），然而，这种方法并不适合常规的UAE分析。考马斯亮蓝染料结合法被认为是间接测量糖尿病患者蛋白尿的一种简单且经济的方法。在本文中，我们比较了RIA法和考马斯染料结合法的化学临床特征，以验证是否真的可以像之前所建议的那样，通过一个简单的线性回归方程从蛋白尿计算出白蛋白尿（反之亦然）。与染料结合法相比，RIA法显示出更好的灵敏度和准确性。我们的研究表明，糖尿病患者的蛋白尿和白蛋白尿之间不存在线性关系。事实上，用染料法测量的总蛋白尿与用特异性和灵敏的RIA法测量的白蛋白尿之间的比值，在有或无肾小球肾病的糖尿病患者中差异很大。虽然染料结合法似乎是检测总微量蛋白尿的最佳方法，因为它精确、便宜且可行，但RIA法因其高灵敏度和特异性，更适合早期准确检测微量白蛋白尿，也适合对有发展为显性糖尿病肾病风险的受试者进行密切随访。
