Evaluating the concordance, prevalence, and risk factors of latent tuberculosis infection among healthcare workers in Makkah: A comparative analysis of TST and IGRA

Background Latent tuberculosis infection (LTBI) poses a significant occupational health risk for healthcare workers (HCWs), particularly in regions with moderate TB burden. The Tuberculin Skin Test (TST) and Interferon-Gamma Release Assay (IGRA) are widely used for LTBI screening, but their concordance and diagnostic performance remain controversial. This study aims to assess the prevalence of LTBI among HCWs in the Makkah region, evaluate risk factors, and compare the diagnostic accuracy and concordance of TST and IGRA METHODS: A cross-sectional study was conducted among 400 HCWs in Makkah. Demographic and occupational data were collected, and LTBI was assessed using TST and IGRA. Both tests' sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Multivariate logistic regression was performed to identify independent risk factors for LTBI. A composite LTBI risk score was developed to evaluate the combined effect of multiple risk factors. The concordance between TST and IGRA was assessed using the Kappa coefficient RESULTS: The prevalence of LTBI was 26.3 % (n = 105) by TST and 19.5 % (n = 78) by IGRA. IGRA demonstrated higher sensitivity (92 %) and specificity (95 %) compared to TST (sensitivity: 86 %, specificity: 60 %). The concordance between TST and IGRA was moderate (Kappa coefficient = 0.62). Age ≥ 35 years, frequent contact with TB patients, and smoking were significant risk factors for LTBI (p Conclusion IGRA outperforms TST regarding diagnostic accuracy and is less affected by prior BCG vaccination. The moderate concordance between the two tests highlights the need to carefully select screening methods, particularly in occupational settings. Identifying HCWs at higher risk using a composite risk score can enhance targeted screening and preventive strategies. While IGRA demonstrated more favorable diagnostic performance metrics than TST in this setting, these findings should be interpreted cautiously due to the absence of confirmatory testing. Nonetheless, the results support its potential utility in guiding targeted screening strategies among high-risk healthcare workers.