2nd Department of Internal Medicine-Division of Clinical Hematology, Charles University Faculty of Medicine and University Hospital, Sokolska 581, 500 05 Hradec Kralove, Czech Republic.
Clin Biochem. 2011 Apr;44(5-6):403-5. doi: 10.1016/j.clinbiochem.2011.01.008. Epub 2011 Feb 1.
Protein concentration measurement in the urine can be problematic in the presence of Bence Jones protein. We have carried out an external quality control assessment with the participation of 79 clinical biochemistry laboratories from the Czech Republic and Slovakia.
The laboratories received a reference urine sample obtained from a patient with multiple myeloma and lambda free light chain proteinuria and were asked to type the paraprotein using immunofixation and to measure total urinary protein using their established method, most commonly turbidimetry, pyrogallol red assay, and biuret assay.
There was a very wide inter-laboratory variability in the protein concentration readouts with up to three-fold difference in some cases. High-resolution two-dimensional electrophoresis and linear mass spectrometry showed that a high proportion of the urinary paraprotein was composed of lambda light chain fragments with molecular weight of 12kDa.
Our results highlight the challenges of reliable and reproducible measurement of urinary protein concentration in the presence of Bence Jones protein.
在存在 Bence Jones 蛋白的情况下，尿液中的蛋白浓度测量可能会出现问题。我们在捷克共和国和斯洛伐克的 79 个临床生化实验室参与的情况下进行了外部质量控制评估。
实验室收到了一份来自多发性骨髓瘤患者和游离轻链蛋白尿患者的参考尿液样本，并要求使用免疫固定法对副蛋白进行分型，并使用他们建立的方法（最常见的是浊度法、邻苯三酚红法和双缩脲法）测量总尿蛋白。
在蛋白浓度读数方面存在非常大的实验室间变异性，在某些情况下差异高达三倍。高分辨率二维电泳和线性质谱显示，尿液副蛋白的很大一部分由分子量为 12kDa 的 lambda 轻链片段组成。
我们的结果强调了在存在 Bence Jones 蛋白的情况下可靠和可重复测量尿液蛋白浓度的挑战。
