Kok Maarten B, Tegelaers Frans P W, van Dam Bastiaan, van Rijn Jan L M L, van Pelt Johannes
Medical Center Alkmaar, Laboratory of Clinical Chemistry, Hematology and Immunology, Alkmaar, The Netherlands.
Medical Center Alkmaar, Laboratory of Clinical Chemistry, Hematology and Immunology, Alkmaar, The Netherlands.
Clin Chim Acta. 2014 Jul 1;434:6-10. doi: 10.1016/j.cca.2014.03.035. Epub 2014 Apr 5.
Several investigators have reported discrepancies between the bromocresol-purple (BCP), bromocresol-green (BCG) and immunonephelometric (INP) assays in dialysis patients. This study compared the abovementioned assays and investigated whether hemodialysis itself or carbamylation of albumin is the cause for this discrepancy.
Samples obtained from hemodialysis patients were analyzed by BCP, BCG and INP. Furthermore, albumin was carbamylated in vitro using isocyanate. Isocyanate converts lysine to homocitrulline.
No differences were observed between samples of the pre- and post-hemodialysis groups for BCP. In the control group, BCG averaged 6 g/L higher than INP. BCP did not statistically deviate from INP. In the dialysis group BCG averaged 5 g/L higher when compared to INP, whereas BCP averaged 2 g/L lower. BCP was affected by carbamylation of albumin. BCG and INP measurements were affected to a much lesser extent. Homocitrulline content of hydrolysates was increased in both the carbamylated albumin as well as in the dialysis population.
In a hemodialysis population albumin concentrations are not consistently estimated by both BCG and BCP methods. Relative to INP measurements BCG overestimates the albumin concentration (4-10 g/L), whereas BCP leads to an underestimation (0-4 g/L). Carbamylation of albumin is the main attributor to the discrepancy found with BCP.
几位研究者报告了透析患者中溴甲酚紫（BCP）、溴甲酚绿（BCG）和免疫比浊法（INP）检测结果之间存在差异。本研究比较了上述检测方法，并调查血液透析本身或白蛋白的氨甲酰化是否是造成这种差异的原因。
采用BCP、BCG和INP对血液透析患者的样本进行分析。此外，使用异氰酸酯在体外使白蛋白氨甲酰化。异氰酸酯将赖氨酸转化为高瓜氨酸。
血液透析前、后组样本的BCP检测结果未观察到差异。在对照组中，BCG平均比INP高6 g/L。BCP与INP在统计学上无偏差。在透析组中，BCG平均比INP高5 g/L，而BCP平均低2 g/L。BCP受白蛋白氨甲酰化的影响。BCG和INP测量受到的影响要小得多。氨甲酰化白蛋白和透析人群中水解产物的高瓜氨酸含量均增加。
在血液透析人群中，BCG和BCP方法对白蛋白浓度的估计并不一致。相对于INP测量，BCG高估了白蛋白浓度（4 - 10 g/L），而BCP导致低估（0 - 4 g/L）。白蛋白的氨甲酰化是BCP检测结果出现差异的主要原因。
