Abstract:

Objective To investigate the application of the Clinical and Laboratory Standards Institute（CLSI） document EP06-Ed2 in the linear verification of quantitative measurement procedures,taking triiodothyronine（T₃） and free triiodothyronine（FT₃） as examples. Methods The samples close to the upper and lower limits of the linear interval were selected,7 samples were prepared proportionally,and each sample was repeated for determination twice. A weighted linear regression analysis was performed using dilution ratios and means（x）. The predicted value was calculated,and the 95% confidence interval（CI） of linear deviation was compared with the allowable deviation from linearity（ADL）. When the CI of all samples overlapped with ADL,the linearity of the whole interval was acceptable. Results The linear deviation 95%CI of samples No. 1-6 of T₃ was within the ADL,and the linear deviation of sample No. 7 was within the ADL. The linear deviation 95%CI of samples No. 2-4 of FT₃ was within the ADL,the linear deviation of samples No.1 and No.5 was within the ADL,and the linear deviation of sample No. 6 was not within the ADL,but the linear deviation 95%CI overlapped with the ADL,sample No. 7 linear deviation 95%CI was not within the ADL. Conclusions Compared with EP06-A,CLSI EP06-Ed2 has clearer and more reasonable requirements for the selection of linear sample concentration,with more effective and simple datum analysis and processing. It is a practical guide for the linear verification of quantitative measurement procedures.

Key words: Linear interval, Verification, Confidence interval, Allowable deviation from linearity, EP06-Ed2 document