Objective: To optimize the detection conditions and evaluate of cystatin C(CysC) by liquid protein microarray.
Methods: CysC was detected by double antibody sandwich method using liquid protein microarray. On the basis of determining the optimal concentration combination of captured antibody and detected antibody, the detection conditions were optimized by determining the biological detection limit and lower detection limit, drawing the S-shaped curve and judging the linear range, and establishing the standard curve and regression equation. Methodsologically evaluate the accuracy, precision, reportable range and analytical specificity of the detection method.
Results: The optimal concentration combinations of CycC trapping-detection antibodies were 26.6 μg/mL-1∶800. The lower limits of detection and biologic limits of detection of the CysC were 0.037 and 0.237 ng/mL, respectively. Regression equation were as followes: y=-3.315x~2+283.04x+160.89, R~2=0.9921. The relative bias of CysC which was detected on the liquid protein microarry was 5.81%. The dilution recovery and recovery were 70.35%-84.91%(n=3)and 79.94%-122.41%(n=3)respectively. The correlation coefficient of method ology comparison experiment was r=0.616, P<0.05, and there was no significant difference between the two method(t=0.948, P=0.358); The within-run precision range from 3.54% to 4.03%(n=10); The between-run precision range from 12.07% to 15.05%(D=5, n=3); The reportable range was 0.26-3784.04 ng/mL. The analysis of interference test result showed that the both concentrations of hemoglobin(160.00, 71.11 g/L) had interference to the result of CysC detected on the chip.
Conclusion: This study completed the optimization of conditions and methodological evaluation of liquid protein microarray in detecting CysC.
Keywords: conditional optimization; cystatin C; liquid protein microarray; methodological evaluation.