Objective To analyze the supplementary test results of HIV screening positive samples in Jianyang City, Chengdu from 2019 to 2022, to evaluate different HIV testing methods, and to provide a basis for the development of HIV testing strategies in the local area.

Methods Western blotting (WB) supplementary test was conducted on 1 172 screening positive samples from the HIV confirmatory laboratory in 2019‒2022 according to the national technical specifications. The samples were tested by the rapid test, enzyme-linked immunoassay (ELISA), and chemiluminescence immunoassay (CLIA). The test results of the three HIV screening methods were collected and a database was established for statistical analysis.

Results A total of 1 172 samples were tested through supplementary test, of which 1 022 samples were tested positive (87.20%), 75 were uncertain (6.40%), and 75 were negative (6.40%). The positive results of the three different HIV screening methods were consistent with the supplementary test. The rapid test had the highest positively supplementary rate of 88.54%, followed by ELISA of 86.98%, and CLIA of 85.92%. The difference was statistically significant (χ²=9.505, P<0.05). The detection rate of WB band patterns in positive samples were the highest at 100.00% for gp160 and gp120, and lowest at 50.68% and 63.41% for p55 and p17, respectively. The WB band patterns of uncertain samples were mainly gp120 (81.33%) and p24 (46.67%). Among the 75 uncertain samples, 39 were followed up and 29 of which turned positive, with a high positive conversion rate of 74.36%.

Conclusion It is necessary to directly add HIV nucleic acid testing to samples with positive WB supplementary test results and samples with uncertain WB supplementary test results in combination with CLIA, so as to avoid the spread of HIV infection caused by missed detections.