Objective To evaluate the detectability of HIV antigen-antibody in the window period of acute infection by three HIV antigen-antibody assays.Methods Twenty-two samples of HIV seroconversion serum panels and thirty-seven HIV acute infected plasm samples from our laboratory collected from cohort study of men who have sex with men between 2009 and 2011,were assayed by ECLIA,CLIA and ELISA methods.All assays were evaluated for the ability to detect HIV in the window period,and the sensitivity of each assay for acute samples was analyzed.Chi square test was used for statistical analysis.Results The ability of detecting HIV in the window period of each assay was different.For HIV seroconversion serum panels,the results of ECLIA and CLIA assays were consistent,and the window period was shortened at least 1 to 5 days compared with ELISA assay.For HIV acute samples,all were HIV positive by ECLIA or CLIA assay,but for ELISA assay,94.6％ was positive.For samples before seroconversion,ECLIA and CLIA assay had the same sensitivity (93.5％),which is superior to ELISA assay (71.0％) (x2 =5.14,P ＜0.05).Conclusion The ability of detecting HIV in the window period was different for each assay.The results of ECLIA and CLIA assay are consistent,superior to ELISA assay.

Objective To compare the performance of fourth generation HIV antigen/antibody combined detection reagents for HIV early infection samples,international HIV seroconversion panel samples and routine clinical screening samples.Methods Thirty seven early HIV infected samples from the followup gays in Shen Yang between 2009 and 2011,66 seroconversion panel samples from BBI company (U.S.A),NABI company(U.S.A) and NIBSC company(U.K) and 703 routine HIV screening samples in the first hospital of China medical university in October 2010 were collected.All kinds of samples were tested by three diagnostic reagents based on chemiluminescence assay (CLIA),electrochemiluminescence assay (ECLIA) and enzyme-linked immunosorbent assay (ELISA) respectively.The detection sensitivity and specificity of these assays were analyzed.Results For 59 early infected and seroconversion samples,the sensitivities of both ECLIA and CLIA reagent were 96.61％ (95％ CI 91.5％-100.0％),higher than that of the ELISA kit (95％ CI 75.0％-92.9％) (x2 =5.341,P ＜ 0.05),which is 83.93％ ; Comparison among the three reagents for different subtypes of the antibody seroconversion samples showed that ECLIA had the highest sensitivity while CLIA was the lowest ; Detection sensitivity of the three reagents for the P24 antigen is CLIA ＞ ECLIA ＞ ELISA; With detection of 703 clinical routine screening samples,the specificities of three reagents were 100％ (CLIA),99.86％ (ECLIA) and 99.71％ (ELISA) respectively.Conclusions For the sensitivity of the fourth HIV diagnostic reagents CLIA and ECLIA are better than ELISA.The former two reagents are more suitable for identifying earlier HIV infection in clinic.