Accuracy and safety of C-TST for tuberculosis infection: A clinical trial in Brazil.
PulmonologyJul 17, 2026 (epub)
Clinical ResearchInfectious Diseases
Marcela Bhering, Carla Conceição, Martha Oliveira et al.
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In 30 seconds
This randomized controlled trial evaluated the accuracy and safety of the C-tuberculin skin test (C-TST) compared to PPD RT-23 for diagnosing tuberculosis infection in BCG-vaccinated adults in Brazil. Among 446 participants, C-TST demonstrated lower sensitivity (0.67) but higher specificity (0.92) than PPD RT-23, indicating its potential as a screening tool in high-burden settings.
Key findings
- C-TST sensitivity was 0.67 and specificity was 0.92 at the 5-mm cut-off.
- PPD RT-23 sensitivity was 0.74 and specificity was 0.78.
- Adverse events occurred in 12.1% of C-TST and 6.4% of PPD RT-23 participants.
- Adding erythema to C-TST readings did not improve accuracy.
Why it matters
Accurate diagnosis of tuberculosis infection is crucial, especially in high-burden areas. The findings suggest that C-TST may provide a reliable alternative for screening in BCG-vaccinated populations, potentially improving public health strategies.