Screening for Latent Tuberculosis Across Chronic Kidney Disease Stages Using Interferon-Gamma Release Assay: Findings from a National Infectious Disease Institute in Thailand

Background: Latent tuberculosis infection (LTBI) is a major global health concern, particularly among individuals with chronic kidney disease (CKD), who are at increased risk of reactivation due to impaired immunity and frequent exposure to immunosuppressive therapies. Despite growing reliance on interferon-gamma release assays (IGRAs) such as QuantiFERON-TB Gold In-Tube (QFT-GIT) in BCG-vaccinated populations, data on IGRA performance across CKD stages remain limited in resource-limited settings. Objective: To determine the prevalence of LTBI and indeterminate IGRA results across CKD stages in a Thai population and assess the clinical utility of IGRA in this context. Materials and Methods: We conducted a cross-sectional study among 785 Thai adults receiving care at a national infectious disease institute, including diabetes clinic patients, hospital staff, and individuals on hemodialysis. Each participant underwent QFT-GIT testing, and the CKD stage was classified using the estimated glomerular filtration rate (eGFR) closest prior to testing. Results: Overall IGRA positivity was 22.2%, peaking in CKD stage G3 (31.6%) and declining in stage G5 (11.0%), where indeterminate results were also highest (6.8%). Limitations: Single-center design and lack of confirmatory testing may limit generalizability. Conclusions: IGRA performance is reliable in early-to-moderate CKD but less so in advanced stages. LTBI is prevalent in CKD stages G2–G4, supporting stage-specific approaches to LTBI screening and caution against overreliance on IGRA in advanced renal impairment.