Bias of measurement results of different methods determining high sensitivity C-reactive protein according to the guideline approved by CLSI

Objective To analyze the bias of measurement results using different methods determining high sensitivity C-reactive protein(Hs-CRP).Methods According to the EP9-A file approved by Clinical Laboratory Standardization Institute(CLSI),three test methods were compared with the comparison method,which formed three comparison groups.The comparison data in each group were presented in scatter figures and bias figures showing the linear equations and correlation coefficients while the biases of measurement results were evaluated.Results In each comparison group,the measurement results using the test method were well correlated with the results using the comparison method(r2=0.991 8,0.986 8,0.996 7).While Hs-CRP was 3 mg/L,three predicted relative biases were respectively 6.4%,32.3% and 24.4%.Conclusions The measurement results of Hs-CRP by the particle-enhanced immunoturbidimetric assay using different reagent kits were coincided with each other.The bias of Hs-CRP measurement results between the particle-enhanced immunoturbidimetric assay and the particle-enhanced immunonephelometric assay was considerable.Comparing the method determining independently Hs-CRP with that determining simultaneously both Hs-CRP and CRP,the former can reduce the bias of Hs-CRP measurement results.