Table 1 Latent tuberculosis classification
HIV serostatus | TST induration | TST qualitative | IGRA IU/mL | LTBI Class |
|---|---|---|---|---|
Negative HIV Ab | ||||
 Negative | 0-9 mm | Negative | n/a | No LTBI |
 Negative | 10-14 mm | Positive | Any | Low reactor |
 Negative | ≥15 mm | Positive | 0.35–0.99 | Low reactor |
 Negative | ≥15 mm | Positive | ≥1.00 | High reactor |
Positive HIV Ab | ||||
 Positive | 0 | Negative | n/a | No LTBI |
 Positive | 1-4 mm | Positive | Any | Low reactor |
 Positive | ≥5 mm | Positive | Any | High reactor |
Unknown HIV Ab | ||||
 Unknown | 0 | Negative | n/a | No LTBI |
 Unknown | 1-9 mm | Uninterpretable | Any | Undetermined |
 Unknown | 10-14 mm | Positive | Any | Undetermined |
 Unknown | ≥15 mm | Positive | 0.35–0.99 | Undetermined |
 Unknown | ≥15 mm | Positive | ≥1.00 | High reactor |