溴甲酚绿法与免疫比浊法联合应用避免尿微量白蛋白检测假阴性结果

Combined application of bromocresol green method and immunoturbidimetry to avoid false negative results in urinary microalbumin detection

目的 预防尿微量白蛋白(mALB)检测因发生钩状效应导致结果与临床实际情况不符,对发生钩状效应的标本使用溴甲酚绿法联合检测,并验证其可行性。方法 收集2023年1月—2023年5月武警重庆总队医院检验科的20份新鲜高白蛋白尿液标本,根据免疫比浊法按原倍或稀释模式确定理论浓度;考虑到溴甲酚绿法的检测低限和检测线性范围上限,将溴甲酚绿法样本增量5倍定位浓度梯度。将免疫比浊法标准样本量测定白蛋白的结果与理论浓度绘制曲线,评估钩状效应。同时采用溴甲酚绿法取样本增量5倍检测,每份样本检测3次,计算均值、变异系数(CV)以及与已知理论浓度的偏移(Bias)。评估发生钩状效应的标本使用溴甲酚绿法检测的可行性。结果 当尿mALB浓度大于1 082 mg/L时,免疫比浊法出现钩状效应,直接测定结果与临床不相符。而溴甲酚绿法在尿mALB浓度达到412 mg/L时,样本增量5倍测定结果可满足临床要求。结论 在尿mALB浓度达到412 mg/L时,可用溴甲酚绿法样本增量5倍测定替代免疫比浊法,两种方法联合应用可避免尿mALB检测结果因发生钩状效应导致与临床实际情况不相符。

Objective To prevent the occurrence of discrepancies between urinary microalbumin(mALB)detection results and clinical actual situation due to hook-like effect,using bromocresol green method in combination with detection for specimens with hook-like effect,and to verify its feasibility.Methods Twenty fresh high-albumin urine samples were collected from the clinical laboratory department of Chongqing Armed Police Force Hospital from January 2023 to May 2023,and the theoretical concentration was determined according to the immunoturbidimetric method in original fold or dilution mode.Considering the low limit of detection and the upper limit of detection linear range of bromocresol green method,the concentration gradient of bromocresol green method was determined through increasing the sample by 5 times.The results of albumin determination with standard sample capacity of immunoturbidimetry and theoretical concentration were plotted to evaluate the hook-like effect.At the same time,bromocresol green method was used to detect the sample size increasing by 5 times,each sample was tested for 3 times,and the average value,coefficient of variation(CV)and deviation from the known theoretical concentration(Bias)were calculated.The feasibility of using bromocresol green method to detect samples with hook-like effect was evaluated.Results When the urinary mALB concentration was greater than 1082 mg/L,the hook-like effect appeared by immunoturbidimetry,and the direct results were not consistent with the clinical results.When the concentration of urinary mALB reached 412 mg/L,the results of sample increment for 5 times could meet the clinical requirements.Conclusions When the concentration of urinary mALB reaches 412 mg/L,the bromocresol green method with 5 times increase of the sample could be used to replace the immunoturbidimetric method.The combined detection of the two methods could avoid the incompatibility of the detection results of urinary mALB due to hook-like effect.