The synergistic impact of serology and nucleic acid test to enhance blood transfusion safety: a retrospective observational study among blood donors at tertiary care hospital in Pakistan

ABSTRACT Objective This study aimed to evaluate the impact of combined use of chemiluminescent immunoassay (CLIA) and nucleic acid amplification testing (NAAT) to improve transfusion transmitted Hepatitis B Virus (HBV), Hepatitis C virus (HCV) and Human Immunodeficiency Virus-1 (HIV-1) among blood donors in Pakistan. Design Retrospective, single center observational. Setting Regional blood center at tertiary care hospital in urban Pakistan. Participants All adults of 18 years or above who were eligible to donate blood after meeting the pre-donation screening criteria during the study period (n = 26,778). Outcome Measures Primary outcome measure was to estimate the incremental yield of HBV, HCV, and HIV-1 infections using combined CLIA+NAAT compared to CLIA-alone per 100,000 donations. Secondary outcome was to calculate inter-test agreement and discordance between CLIA and NAAT methods. Results Among 26,778 donors, the combined CLIA+NAAT testing detected a total of 2,423.6 viral infections per 100,000 donations, NAAT alone contributed 739.7/100,000 of these. For HBV, NAAT uniquely detected 489/100,000 additional cases missed by CLIA; the combined detection rate was 1,561/100,000. For HCV, NAAT-only yield was lower (247/100,000), with total detection of 825.3/100,000. HIV-1 was rare in the donor pool; incremental NAAT yield was 3.7/100,000, with a combined detection rate of 37.3/100,000. Agreement between tests was substantial for HBV (κ = 0.63) and moderate to fair for HCV (κ = 0.47) and HIV-1 (κ = 0.40). The discordant cases detected by NAAT alone for HBV, HCV and HIV-1 were 183, 431 and 37 respectively. McNemar’s test showed statistically significant differences (p < 0.001) across all markers, with large effect sizes for HIV-1 (0.92, 95% CI: 0.80–1.00) and HCV (0.69, 95% CI: 0.65–0.73). Conclusion Integrating CLIA with NAAT enhanced the detection of HBV, including occult and window period infections, and refined estimates of active HCV and HIV-1 infections which significantly improved blood transfusion safety. STRENGTHS AND LIMITATIONS OF THIS STUDY The selection bias was reduced by including all consecutive eligible blood donors during study period. The information bias was minimized through uniform, fully automated, and validated protocols for combined CLIA and NAAT testing of blood donors. The single center retrospective study design restricts generalizability and causal inference. The false positives/negatives and genetic variability were not confirmed.