Abstract: Objective  To establish a quantitative double-antibody sandwich light initiated chemiluminescence assay (LiCA) for the determination of plasma myeloperoxidase (MPO) concentration in order to assist to diagnose cardiovascular diseases.  Methods  From 12 anti-MPO monoclonal antibody (McAb), the optimum double-antibody combination (one McAb coated on luminescence particles and the other McAb conjugated with biotin) was picked out by the checkerboard titration. The suitable reaction concentration and conditions were analyzed. Consequently, the repeatability, sensitivity, anti-interference and recovery rate of the assay were evaluated and compared with the classic CardioMPO^TM enzyme-linked immunosorbent assay (ELISA).  Results  Two McAbs were selected successfully. The quantitative MPO LiCA system was constructed by connecting the sensitizer particles with streptavidin. The results showed that the sensitivity was 1.76 ng/mL. The within-run and interday-run coefficients of variation (CV) of MPO LiCA were 2.73％ and 3.76％ respectively, and the mean recovery rate was 102.5%±8.6%. The correlation with CardioMPO^TM ELISA was high (r=0.961，P<0.01). The normal reference range was 13.16-128.79 ng/mL. Conclusions  A quantitative LiCA for the determination of MPO is successfully established. MPO LiCA with good sensitivity, stability, long reagent validity, simple and convenience shows a better application prospect in assisting to diagnose cardiovascular diseases.

Key words: Myeloperoxidase, Light initiated chemiluminescence assay, Enzyme-linked immunosorbent assay, Monoclonal antibody