Kahana L, Yechieli H
Central Endocrine Laboratory, Linn Medical Center, Haifa, Israel.
Clin Chem. 1991 Aug;37(8):1432-6.
The Israel External Quality-Assessment scheme (EQAS) provided service from 1985 to 1989, primarily to laboratories in Israel. Participation was voluntary and confidential, and involved 30-35 laboratories performing thyroid-related function tests. Scheme design included 36 human serum specimens distributed to the participants at the beginning of each year. For 12 months, three specimens were analyzed each month and the results were reported to EQAS on pre-agreed dates. Monthly reports sent by EQAS to participants after analysis of the results included the overall consensus mean used as target value, between-laboratory agreement, individual laboratory bias, and recovery data. The overall consensus mean calculated as all-laboratory trimmed mean was validated by reproducibility and recovery studies. Samples with undetectable concentrations of thyrotropin (TSH), obtained from patients proven thyrotoxic, were used to validate measurement of very low TSH concentrations. During the scheme, liquid serum was found superior to lyophilized specimens for distribution to the participants. The scheme helped stimulate major improvements in between-laboratory agreement, especially for low TSH concentrations, with CVs decreasing from 180% in the first year to 20% in the fourth year. Each laboratory's performance also improved as judged by the median bias and variability of bias and by the considerable decrease in the number of laboratories with unacceptable performance for all tests. Method-related differences in performance were observed despite the small number of participants. Better methods, e.g., a radioimmunometric method for TSH, were detected and adopted by the participants, with concomitant improvement in performance. Transfer to analog procedures for free thyroxin, in addition to, but mostly instead of, thyroxin, was also documented, with no gain in analytical performance. Despite this being a small scheme, most of the goals achievable with a large scheme were realized.
以色列外部质量评估计划（EQAS）于1985年至1989年提供服务，主要面向以色列的实验室。参与是自愿且保密的，有30 - 35个进行甲状腺相关功能测试的实验室参与其中。计划设计包括每年年初向参与者分发36份人血清标本。在12个月内，每月分析3份标本，并在预先商定的日期将结果报告给EQAS。EQAS在分析结果后向参与者发送的月度报告包括用作目标值的总体共识均值、实验室间一致性、单个实验室偏差和回收率数据。作为所有实验室截尾均值计算的总体共识均值通过重复性和回收率研究进行了验证。从经证实患有甲状腺毒症的患者中获得的促甲状腺激素（TSH）浓度不可测的样本，用于验证极低TSH浓度的测量。在该计划期间，发现液体血清在分发给参与者方面优于冻干标本。该计划有助于推动实验室间一致性的重大改进，特别是对于低TSH浓度，变异系数从第一年的180%降至第四年的20%。从所有测试中表现不可接受的实验室数量大幅减少以及中位数偏差和偏差变异性来看，每个实验室的性能也有所提高。尽管参与者数量较少，但仍观察到性能方面与方法相关的差异。参与者发现并采用了更好的方法，例如TSH的放射免疫分析法，同时性能也有所提高。还记录了向游离甲状腺素模拟程序的转变，除了甲状腺素外，主要是替代甲状腺素，且分析性能未得到提升。尽管这是一个小规模计划，但实现了大规模计划可实现的大部分目标。
