<![CDATA[Background: Tuberculosis (TB) diagnosis is routinely established through sputum-based testing. However, obtaining high-quality sputum samples remains challenging, particularly for molecular diagnostic methods. Saliva has emerged as an attractive alternative specimen because it is safe, non-invasive, and easy to collect.Objective: This study aimed to evaluate the diagnostic accuracy of Xpert MTB/RIF Ultra in saliva compared with sputum as the reference standard for detecting Mycobacterium tuberculosis (MTB) and rifampicin resistance.Methods: This preliminary diagnostic accuracy study employed a cross-sectional design and included 22 patients with suspected TB attending a pulmonary outpatient clinic. Each participant underwent parallel Xpert MTB/RIF Ultra testing using paired sputum and saliva samples. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios, and overall diagnostic accuracy were calculated using 2×2 contingency table analysis, with sputum Xpert MTB/RIF Ultra serving as the reference standard.Results: The results of this study showed that 22 subjects were included. MTB was detected in sputum samples from 16 subjects and in saliva samples from 13 subjects. Among respondents examined using both specimens, 11 had positive results, and 4 had negative results. Saliva examination produced five false-negative and two false-positive results. The sensitivity was 68.8%, the specificity was 66.7%, the PPV was 84.6%, and the NPV was 44.4%. At low bacterial concentrations, the results of this study were more likely to be unfavourable. The likelihood ratios were LR⁺ 2.06 and LR⁻ 0.47, indicating that sputum examination cannot yet be replaced. However, based on this study’s results, saliva has potential as a screening test, particularly in primary healthcare settings.Conclusion: Saliva represents a practical alternative specimen in cases where sputum collection is problematic and may support earlier detection of tuberculosis ]]>
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