Study on the effect of HIV antibody re-examination with two kinds of reagents

Objective To explore the screening test procedure for HIV antibody detection suitable for laboratory requirement. Methods From August 1, 2015 to December 31 2016, 873 primary screening positive specimens from AIDS confirmation laboratory in the Clinical Laboratory Center of Beijing youan hospital were collected. All the samples were rechecked using the same reagents (strategy 1) and two other different reagents (strategy 2), and then the HIV antibody supplementary experiment was detected according to the results of the recheck. Chi-square test was used to compare the statistical difference of HIV antibody screening positive predictive values (PPV) among the two strategies. Results In both strategies, 786 were detected HIV antibody positive, including 754 WB positive, 23 follow-up WB positive and 9 nucleic acid positive. The HIV antibody screening PPV of strategy 1 and strategy 2 were 90.0 % (786/873) and 95.9 % (786/820), respectively, and the difference was statistically significant (x2=21.58, P<0.01). As it to STD clinic cases, the HIV antibody screening PPV for strategy 1 and strategy 2 were 92.9 % (745/802) and 97.3 % (745/766), respectively, and the difference was statistically significant (x2=15.80, P<0.01); As it to general out–patients, The HIV antibody screening PPV for two strategies were 57.7 % (41/71) and 75.9% (41/54), respectively. the difference was statistically significant (x2=4.49, P=0.03). Conclusions When using HIV antibody screening strategies, it is recommended that two other reagents should be used for re-examination to improve diagnostic specificity in the group of people with high prevalence of HIV, as the patients in STD clinics. Key words: HIV; Antibodies; Antibody detection; Diagnostic strategy