Table 1.
Current TST methods used for LTBI diagnosis
| Characteristics | PPD | C-TB | Diaskintest | EC-test |
|---|---|---|---|---|
| Time | > 100 years | 2009 | 2010 | 2020 |
| Type of reaction | DTH | DTH | DTH | DTH |
| Number of visits | 2 | 2 | 2 | 2 |
| Type of antigen | PPD | ESAT-6 and CFP-10 | ESAT-6 and CFP-10 | ESAT-6 and CFP-10 |
| Outcome measures | Millimeters of induration | Millimeters of induration | Millimeters of induration | Millimeters of induration |
| Sensitivity |
77% [190] 84% [191] |
73.9% [189] 74.52% [192] |
86% [193] 68% [193] 91.18 [192] |
90.85% [194] 86.06% [192] |
| Specificity |
97% (without BCG vaccination) and 59% (with BCG vaccination) [190] 100% (without BCG vaccination) and 79% (with BCG vaccination) [191] |
97.85% [192] | 98% [193] | 89.83% [194] |
| Interpretation | Subjective | Subjective | Subjective | Subjective |
| False positive rate in immunosuppressed or BCG vaccinated population | High | Low | Low | Low |
| Distinguish between LTBI and ATB | No | No | No | No |
ATB active tuberculosis, BCG Bacillus Calmette–Guérin, CFP-10 culture filtrate protein-10, DTH delayed type hypersensitivity, ESAT-6 early secreted antigen target-6, LTBI latent tuberculosis infection, TST tuberculin skin test, PPD purified protein derivative, C-TB a novel skin test based on ESAT-6 and CFP-10 proteins, EC recombinant Mycobacterium tuberculosis fusion protein of ESAT-6 and CFP-10