Abstract: Objective　To establish and evaluate the limit of blank（LoB），the limit of detection（LoD） and the limit of quantitation（LoQ） of high-sensitivity assays for cardiac troponin I（cTnI） on chemiluminescence immune analyzer.   Methods　According to the document EP17-A published by Clinical and Laboratory Standards Institute（CLSI），cTnI blank samples and serial low concentration samples were detected by BECKMAN-COULTER DXI800 chemiluminescence immune analyzer（DXI800）. Based on the data distribution，by relevant statistical methods，the LoB，LoD and LoQ of cTnI were calculated. Simultaneously，by the traditional methods，the low limit of detection（LLD），biological limit of detection（BLD） and function sensitivity（FS） were established. Results　According to CLSI EP17-A document，the LoB was 3.5ng/L，the LoD was 11.5ng/L，and the LoQ was 30 ng/L. The LLD was 5.4 ng/L，the BLD was 10-20 ng/L，and the FS was 30 ng/L by the traditional methods. Conclusions　The LoB and LLD are both lower than the sensitivity performance of the manufacturer declaration. The analysis sensitivity of cTnI by DXI800 is validated. The established LoB，LoD，LoQ and FS of cTnI in the laboratory provide more accurate and reliable results.

Key words: Cardiac troponin I, High-sensitivity assay, Methodological evaluation