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Abstract

Objective: This study aimed to analyze ELISA, ECLIA, and Western blot (WB) confirmatory test results for HIV-reactive blood donors, compare ECLIA with fourth-generation ELISA reagents, assess the feasibility of using ECLIA for HIV screening, and provide statistical evidence supporting its adoption in blood collection and supply institutions.
Methodology: The cross-sectional study was conducted in the Laboratory Department of Yantai Central Blood Station, Shandong, China, from January, 2021 to December, 2023. A total of 130 HIV screening-reactive specimens with ELISA signal-to-cut-off (S/CO) ratios between 0.3 and 0.7 were subjected to ECLIA. Specimens with ELISA S/CO≥1.0, HIV RNA reactivity, or ECLIA S/CO>1 were sent to the Centers for Disease Control (CDC) for WB confirmatory testing. The results were comprehensively analyzed and compared.
Results: Among the 130 reactive specimens, 17 tested positive by ECLIA, while 113 were negative. Of the 510 HIV screen-negative specimens, five were positive by ECLIA, and 505 were negative. ECLIA demonstrated a sensitivity of 81.25%, specificity of 96.49%, positive predictive value of 76.47%, and negative predictive value of 97.35%. ECLIA showed excellent concordance with WB confirmatory results, evidenced by the highest area under the operating characteristic (ROC) curve (AUC). The sensitivities of reagent one, reagent two, and ECLIA were consistent at different cut-off values; however, ECLIA exhibited the highest specificity.
Conclusion: ECLIA exhibits superior agreement with WB confirmatory tests, higher specificity, and positive predictive values compared to ELISA reagents, supporting its widespread use in blood screening.