Performance Validation and Refinement of a Clinical Tuberculosis Score: A Retrospective Cohort Study Proposing a Novel Dynamic Scoring Model

Abstract Background The Al Khor, Hamad Medical Corporation, Doha, Qatar, TB Score is used in emergency departments to screen patients with suspected pulmonary tuberculosis (TB) and to support early isolation decisions. Although used operationally, its diagnostic performance had not been formally assessed in the study setting. Objective To evaluate the diagnostic accuracy of the original TB Score, identify an operationally useful cut-off, and describe a revised TB Score (2) as a hypothesis-generating refinement requiring formal validation. Methods We conducted a retrospective cohort study of 309 male patients evaluated for suspected TB at Hazm Mebaireek General Hospital, Hamad Medical Corporation, Doha, Qatar. Diagnostic accuracy of the original score was assessed using receiver operating characteristic (ROC) analysis. Sensitivity, specificity, predictive values, and 95% confidence intervals were calculated for selected cut-offs. Cut-off selection was guided by the balance between sensitivity and specificity and by Youden Index principles. The proposed TB Score (2) was developed from component-level findings and clinical plausibility; it was not considered a validated predictive model in this retrospective analysis. Results Of 309 patients, 64 (20.7%) had confirmed TB. For the original score, the commonly used cut-off of ≥ 4 was sensitive but poorly specific. A cut-off of ≥ 6 provided a more balanced operational profile, with sensitivity of 79.7% and specificity of 66.9% based on the available score distribution. The numerical AUC estimate and 95% confidence interval were not retrievable from the archived ROC output; this limitation is acknowledged in the manuscript rather than left as a future reporting item. Component analysis suggested that prolonged cough, weight loss, night sweats, epidemiological risk, and overcrowding were more aligned with TB than hemoptysis alone. These findings informed the proposed TB Score (2), including a dynamic symptom-duration approach. Conclusion The original Al Khor TB Score is a useful screening tool, but the current threshold may lead to unnecessary isolation. In this cohort, raising the threshold to ≥ 6 may improve specificity while preserving acceptable sensitivity. TB Score (2) should be interpreted as a promising, hypothesis-generating refinement that requires internal and external validation before clinical adoption.