乙酸乙酯萃取尿游离皮质醇性能验证

Methodology Verification of chemiluminescence for detemination urinary free cortisol extracted by ethyl acetate

目的:评价DXI800检测系统乙酸乙酯萃取法检测尿游离皮质醇的性能,探索建立乙酸乙酯萃取尿游离皮质醇的规范流程。方法:参考美国临床实验室标准化协会(NCCLS)文件,制定性能验证的方案。评价DXI800检测系统测定尿游离皮质醇的正确度、检测范围、批内精密度及批间精密度;并分析换溶复溶剂、震荡时间、离心速度、储存时间等因素对乙酸乙酯游离皮质醇萃取效率中的影响。结果:检测系统测量正确度,最大偏倚为3.11%;标准物质批间精密度为4.38%;乙酸乙酯萃取游离皮质醇最大效率为93.39%;低、高两水平尿液游离皮质醇萃取批内精密度分别为2.17%、1.92%;批间精密度分别为3.30%、2.61%;分析不同换溶复溶剂对萃取效率的影响,结果显示20%分析纯乙醇溶液复溶回收率最高(P<0.05),皮质醇零浓度定标液复溶回收率最低(P<0.05)。尿液萃取时震荡30s,4000r/min离心效果最好(P<0.05),尿液采集后48h内检测差异无统计学意义(P>0.05)。结论:DXI800检测系统测定尿游离皮质醇正确度高,精密度好,检测性能可满足临床需求。乙酸乙酯可有效萃取尿游离皮质醇,20%乙醇溶液是较好的游离皮质醇换溶复溶剂。

Objective:To evaluate the methodology of chemiluminescence for determining urinary free cortisol extracted by ethyl acetate using Beckman DXI800 chemiluminescence analyzer.Methods:According to NCCLS's recommended methods,we designed the evaluation program of detecting urinary free cortisol extracted by ethyl acetate.The trueness and imprecision of Beckman DXI800 chemiluminescence analyzer were evaluated using reference material.The within-run precision and between-run precision of urinary free cortisol extracted by ethyl acetate were evaluated.The effects of solvent,time of votex,speed of centrifuge on the extraction efficiency of free cortisol were also analyzed.Results:The max bias was 3.11%.The max between-run precision of free cortisol was 4.38%.The max extraction efficiency was 93.39%.The within-run precisions of low and high value urinary free cortisol extracted by ethyl acetate were 2.17%and 1.92%,and the between-run precisions were 3.30%and 2.61%.The results showed that the solvent recovery of 20%ethanol solution was the highest and the resolvent recovery of zero concentration cortisol calibration solution was the lowest(P<0.05).Votexing for 30s and centrifuge at 4000r/min has the best effect(P<0.05).There was no difference for detecting cortisol within 48h(P>0.05).Conclusion:The truness,with-run precision and between-run precision of DIX800 for determining urinary free cortisol were excellent and meet the requirement of clinical use.Urinary free cortisol could well be extracted by ethyl acetate.20%ethanol solution could well redissolving urinary free cortisol extracted by ethyl acetate.