Background- Retinol-binding protein4 (RBP) assays using polyclonal antibodies (pRBP) have major problems of non-linearity of dilution and a very small useable dynamic range. Our objective was to develop a specific assay with a wider dynamic range to detect tubular proteinuria.

Methods: mRBP (monoclonal capture and second antibody with colorimetric detection) and fRBP, (polyclonal capture and monoclonal second antibody with fluorescence detection) were developed and compared with pRBP. 488 patient samples were collected- 290 samples were analysed by mRBP and 198 samples with fRBP and compared with pRBP.

Results: mRBP assay has the advantages of better linearity on dilution and wider analytical range over pRBP. It is limited by poor signal in the patients with albuminuria and glomerular proteinuria and inferior discrimination between patient groups. fRBP had an intra-assay and inter-assay CV of <6% and <8% respectively; and analytical range was 2.3-599 µg/L. fRBP was linear on dilution within the analytical range. Correlation (r) was 0.8722(95% CI 0.7621 to 0.9333, p< 0.0001), Mann-Whitney test revealed no significant difference (U= 18877, n=198, p = 0.5244) asserting that the medians of the two samples were identical. Bland-Altman test between pRBP and fRBP showed a mean negative bias of 16.43(CI -994 to 1027) μg/mmol

Conclusion: The combination assay with fluorescence detection (fRBP) proved more discriminatory than a purely monoclonal system especially in patients with significant proteinuria and has advantages of better linearity on dilution and wider analytical range than the existing pRBP assay and compared extremely well with pRBP.

背景-使用多克隆抗体（pRBP）的视黄醇结合蛋白4（RBP）分析存在稀释非线性和可用动态范围非常小的主要问题。我们的目标是开发一种具有更宽动态范围的特异性测定法，以检测肾小管蛋白尿。

方法：开发了mRBP（具有比色检测功能的单克隆捕获和第二抗体）和fRBP（具有荧光检测功能的多克隆捕获和第二抗体），并将其与pRBP进行了比较。收集了488个患者样本，其中290个样本通过mRBP分析，198个样本具有fRBP并与pRBP进行了比较。

结果：与pRBP相比，mRBP测定具有更好的稀释线性度和更宽的分析范围。它受到蛋白尿和肾小球蛋白尿患者信号差以及患者组间分辨力差的限制。fRBP的批内和批间CV分别<6％和<8％。和分析范围是2.3-599 µg / L。fRBP在分析范围内稀释时呈线性关系。相关性（r）为0.8722（95％CI 0.7621至0.9333，p <0.0001），Mann-Whitney检验显示无显着差异（U = 18877，n = 198，p = 0.5244），断言两个样品的中位数相同。pRBP和fRBP之间的Bland-Altman测试显示平均负偏差为16.43（CI -994至1027）μg/ mmol

结论：荧光检测（fRBP）组合检测证明比纯单克隆系统更具歧视性，尤其是在蛋白尿明显的患者中，与现有的pRBP检测相比，具有稀释线性更好，分析范围更广的优势，并且与pRBP相比具有很好的优势。