Publication:

Evaluation of diagnostic outcomes and management of healthcare personnel with positive tuberculin skin tests referred for latent tuberculosis infection assessment at Prince Sultan Military Medical City: a retrospective cohort study

Background Healthcare workers (HCWs) are at increased risk of latent tuberculosis infection (LTBI) due to occupational exposure. However, the diagnostic outcomes, agreement with confirmatory testing, and treatment adherence in this population remain underexplored. This study aimed to evaluate the proportion of TST-positive HCWs diagnosed with LTBI, assess TST-IGRA agreement, and determine treatment initiation and completion rates.

Methods We conducted a retrospective cohort study of 64 HCWs with positive TST results who were referred to the ID clinic at PSMMC from January to December 2025. Data were abstracted from electronic medical records. LTBI diagnosis was defined as positive interferon-gamma release assay (IGRA) or initiation of LTBI treatment. Agreement between TST and IGRA was tested with Cohen's kappa. We used univariate and multivariable logistic regression to identify predictors of LTBI.

Results Of the 64 participants, 40.6% (n=26) were diagnosed with LTBI. IGRA testing was performed in 32.8% (n=21). The agreement between TST and IGRA was poor (kappa=-0.095, p=0.329). Treatment was initiated in 80.8% (21/26) of diagnosed cases, and completion among those who started was 42.9% (9/21). In univariate analysis, nationality (p=0.031), department (p=0.043), and TST size (p=0.014) were significantly associated with LTBI. However, multivariable regression failed to identify independent predictors (overall model p=0.225).

Conclusions Over one-third of referred HCWs were diagnosed with LTBI. TST showed poor agreement with IGRA, highlighting the need for confirmatory testing. Treatment completion rates were suboptimal, suggesting enhanced adherence support strategies are required.