Diagnostic Accuracy of Molecular Testing on Saliva and Oral Swabs for Pulmonary TB [TBN 073]

Who

Individuals aged ≥7 years undergoing microbiologic evaluation for possible TB disease in Cali, Colombia. Of 648 enrolled participants, 596 had final culture results; 95 had culture-confirmed TB. The nested case–control analysis included 190 matched participants with paired saliva and oral swab samples.

What

The study evaluated Xpert-Ultra testing on saliva versus oral swabs for detecting pulmonary TB. Saliva had higher sensitivity than oral swabs: 90.5% vs 71.6%; absolute difference 18.9%; P < .001. Specificity was high for both: 95.8% for saliva and 98.9% for swabs, with no statistically significant difference. Saliva also showed lower Ct values, suggesting greater Mtb DNA recovery.

When

Enrollment occurred from 31 July 2023 to 30 August 2024. Molecular testing occurred a median of 119 days after sample collection.

Where

Two public primary care centers serving the Central and Western Districts of Cali, Colombia.

Why

The study addressed the need for easier, more acceptable, non-sputum-based TB diagnostic samples, especially for people who cannot produce sputum or require induction.

How

Nested case–control study within a prospectively enrolled cohort. Culture-confirmed pulmonary TB cases were matched 1:1 to culture-negative controls by collection date, site, age group, and sex. Saliva and oral swabs were tested using Xpert-Ultra, with MGIT sputum culture as the pragmatic reference standard. Limitations include reliance on a single sputum culture and delayed index testing after sample collection.

Source: Vargas DA, Fuertes-Bucheli JF, Sanchez-Hidalgo A, Palomares Velosa J, Lasso AM, Gupta AJ, Martinez-Valencia AJ, Díaz G, Luna L, Alexander N, Ferro BE. Diagnostic Accuracy of Molecular Testing on Saliva and Oral Swabs for Pulmonary Tuberculosis. Clinical Infectious Diseases. 2026 Mar 12:ciag055. https://benangmerah.net/record/92/diagnostic-accuracy-of