Abstract: Objective To analyze and compare the detective ability of nucleic acid testing Kehua and Daan．Methods Kehua and Daan nucleic acidscreeningsystems were used to detect 56 703 specimens after routine examination qualified and 10 copies of NCCL specimens which had passed the ELISA test beforehand. Statistical analysis was conducted on the effective split ratio and positive ratio of nucleic acid．Results Kehua nucleic acid screening system screened 31,497 specimens and 35 mixed specimens were determined to be positive,among which 23 pools were determined reactive by split testing．The number of reactive samples was 26. The effective split ratio was 65.71%. The positive ratio of specimens was 0.083%. 25 206 specimens were detected by Daan system and 58 mixed specimens were determined to be positive,among which 30 were reactive by split testing,and the number of reactive samples was 34. The effective split ratio was 51.72%. The positive ratio of specimens was 0.135%. 10 cases of NCCL specimens were correctly detected. Conclusion Kehua and Daan screening system shows their own advantages in detecting positive samples from ELISA negative. Both are well fit for routine nucleic acid testing．

Key words: NAT, Nucleic acid screening system, ELISA