Infectious Disease · Public Health · General Practice · 2 h ago
Tongue Swab PCR Shows Low Sensitivity for Asymptomatic Tuberculosis Screening
A diagnostic observational study at six South African sites assessed tongue swab PCR in 834 adults from clinic and household-contact cohorts. High-volume qPCR sensitivity was 63.8% in symptomatic clinic participants versus 34.1% in household contacts with tuberculosis, most of whom were asymptomatic.
- High-volume qPCR sensitivity was 34.1% among household contacts with TB.
- Sensitivity reached 63.8% in symptomatic clinic participants.
- Detection increased with radiographic severity and sputum bacillary load.
- Magnetic capture did not significantly improve sensitivity in clinic participants.
Researchers evaluated tongue swab Mycobacterium tuberculosis PCR for community screening and clinic-based triage at six South African sites. The analysis included 654 symptomatic clinic participants and 180 adult household contacts of people with TB, with propensity-score matching of participants with and without TB. Drug-susceptible pulmonary TB was defined by positive sputum Xpert Ultra, excluding trace results, or liquid culture; all participants underwent both reference tests.
The clinic cohort included 217 participants with TB, while the household-contact cohort included 44, of whom 84.1% were asymptomatic. High-volume qPCR sensitivity was 63.8% in the clinic cohort versus 34.1% among household contacts (P = .0007); specificity was 94.4% and 91.9%, respectively. In clinic participants, sequence-specific magnetic capture with qPCR yielded 73.2% sensitivity and 94.6% specificity, but the sensitivity increase over high-volume qPCR was not statistically significant (P = .14).
Among household contacts, high-volume qPCR sensitivity was 35.1% for asymptomatic TB, 52.2% for TB with an abnormal chest radiograph, and 100% for TB with a high sputum Xpert Ultra grade. These findings indicate limited sensitivity for community screening, with better detection at greater radiographic severity and bacillary load. Interpretation is constrained by the small household-contact TB sample; subgroup denominators and confidence intervals were not provided in the available abstract.
Is this summary clinically accurate?
Help fellow clinicians: your rating sends inaccurate summaries straight to our editors.
Sign in to rate this summary →Source
Clinical Infectious Diseases: Tongue Swab Mycobacterium tuberculosis Quantitative Polymerase Chain Reaction for Community Screening of Asymptomatic Tuberculosis Versus Clinic-Based Triage of Symptomatic Tuberculosis ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.