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Pros and Cons of TST and IGRA
| TST | IGRA |
|---|---|
| Measures skin induration after PPD injection | Detection of IFN-γ |
| Affected by BCG vaccination and other mycobacteria | Unaffected by BCG vaccination and other mycobacteria |
| Less sensitive and specific | More sensitive and specific |
| Cheaper/easy availability | costlier |
| Need for review within 48-72 h | Sample handling difficult |
