Interferon Gamma Release Assay and Tuberculin Skin Test Performance in Pregnant Women Living With and Without HIV

Background HIV and pregnancy may affect latent TB infection (LTBI) diagnostics. Tuberculin skin test (TST) and newer generation QuantiFERON-TB Gold Plus (QFT-Plus) evaluations in pregnant women living with HIV (WLHIV) and without HIV are lacking. Methods In this cross-sectional study, pregnant women underwent TST and QFT-Plus testing during antenatal care in Kenya. We estimated LTBI prevalence and TST and QFT-Plus performances. Diagnostic agreement was assessed with kappa statistic, participant characteristics associated with LTBI and HIV were assessed with generalized linear models, and QFT-Plus quantitative responses were assessed with Mann-Whitney U test. Results We enrolled 400 pregnant women (200 WLHIV/200 HIV-negative women) at median 28 weeks gestation (interquartile range 24-30). Among WLHIV (all on antiretroviral therapy), the median CD4 count was 464 cells/mm3 (interquartile range 325-654); 62.5% (125) had received isoniazid preventive therapy. LTBI prevalence was 35.8% and similar among WLHIV and HIV-negative women. QFT-Plus testing identified 3-fold more women with LTBI when compared with TST (32% vs. 12%, P Conclusions QFT-Plus assay had higher diagnostic yield than TST for LTBI in WLHIV and HIV-negative women despite lower TB-specific antigen responses in WLHIV. Higher TST positivity was observed in WLHIV. LTBI diagnostic performance in the context of pregnancy and HIV has implications for clinical use and prevention studies, which rely on these diagnostics for TB infection entry criteria or outcomes.