The observation of imprecision and linearity on detection of pepsinogen II by latex-enhanced immunoturbidimetry assay

Objective To evaluate primarily the detection of pepsinogen Ⅱ(PGⅡ) by latex-enhanced immunoturbidimetry assay,and provide the reference for clinical application.Methods According to the National Committee for Clinical Laboratory Standards(NCCLS) EP5-A and EP10-A2 documents,the detection of PGⅡ by latex-enhanced immunoturbidimetry assay was evaluated primarily.Results The within-run,between-run,between-day and total coefficients of variation(CV) of samples with low concentration of PGⅡ were 2.05%,1.60%,3.92% and 4.70% respectively.The within-run,between-run,between-day and total CV of samples with high concentration of PGⅡ were 1.70%,1.21%,3.79% and 4.32% respectively.When PGⅡ concentrations were 9.6,24.7 and 39.8 μg/L,the relative biases were-0.18,-0.47 and-0.39 μg/L respectively.The total imprecisions were 4.98%,2.39% and 2.71% respectively.There was no statistical significance in total carry-over(P0.05).The equation of linear regression of PGⅡ was Y =0.975 7X-0.016 8,and the coefficient of determination(R2)= 0.998 7.Conclusions The latex-enhanced immunoturbidimetry assay for the PGⅡ detection with good repeatability meets the clinical application requirements of EP5-A document for precision and the requirements of EP10-A2 document for the linearity,bias,total imprecision and carry-over.It is suitable for the clinical application.