均相酶法检测香草扁桃酸方法学评估及相关指标生物参考区间建立

Analytical performance of VMA by homogeneous enzyme immunoassay and establishment of biological reference intervals of relevant indicator

目的评估均相酶法检测香草扁桃酸(VMA)主要方法学性能;建立适合本地区成年人群随机尿VMA/尿肌酐(Ucr)比值生物参考区间。方法参照美国临床实验室标准化协会(CLSI)EP15-A、EP6-A、EP17-A、C28-A3文件,对精密度、线性范围、定量检测下限,参考区间进行验证。采用两个水平校准品,测定均值,计算均值与靶值的偏倚,验证其准确度;参照CLSI C28-A3,建立随机尿VMA/Ucr比值生物参考区间。收集37例肾上腺疾病及高血压相关疾病患者随机尿及24h尿,分别检测其VMA及Ucr,比较24h尿VMA及随机尿VMA/Ucr之间的相关性。结果均相酶法检测VMA,计算均值与靶值的平均偏倚为17.34%;批内、批间精密度CV<10%;线性范围为1.74~96.77mg/L(R^2=0.989 5);VMA的LoQ为2.2mg/L;健康个体24h尿VMA均在厂家声明参考区间内。随机尿VMA/Ucr比值95%参考区间为(0.333~1.259)×10^(-3) mg/μmol(1.67~6.29μmol/mmol)。肾上腺疾病及高血压患者24h尿VMA与随机尿VMA/Ucr相关性为r=0.579(P<0.01),二者具有明显相关性。结论均相酶法检测VMA主要方法学性能符合实验室要求,满足临床应用;成功建立适合本地区成年人群随机尿VMA/Ucr比值的生物参考区间。

Objective To verify the analytical performance of VMA by Homogeneous Enzyme Immunoassay and to establish of biological reference intervals of VMA/Ucr value in random urine for adult in local area. Methods This verification study validated imprecision,linearity,the limit of quantitation （LoQ）,reference intervals of VMA assay according to the CLSI EP17-P,EP6-A,EP15-A and C28-A3.To assess the accuracy of VMA,we used two- levels manufacturer′s standard material measure the mean and calculate the average bias of test results and target value.According to CLSI C28-A3,we established biological reference intervals of VMA/Ucr value.The random and 24-hour urine of 37 patients with adrenal diseases and/or hypertension-related diseases were collected for VMA and Ucr measured.The 24-hour VMA and VMA/Ucr value in random urine were compared. Results The average bias of VMA of test results and target value was 17.34%;the intra-assay and inter-assay precision were all less than 10%.The linear range was 1.74-96.77 mg/L （ R^2= 0.989 5 ）;LoQ was 2.2mg/L;24-hour VMA of healthy individuals were in the reference range which manufacturers declared.The 95% reference range of VMA/Ucr value in random urine was （0.333-1.259）× 10^ -3 mg/μmol （1.67-6.29 μmol/mmol）.The correlation between 24-hour VMA and random urinary VMA / Ucr value in adrenal and/or hypertension-related diseases was 0.579 （ P 〈0.01）. Conclusion The main analytical performances of VMA detected by homogeneous enzyme immunoassay are in line with laboratory requirements and meet the clinical application.The biological reference intervals of the ratio of VMA/Ucr in random urine for adult population are successfully established.