Used tests for TB | Detection and aim | Pros vs Cons |
Tuberculin skin test | Detection of delayed hypersensitivity to the tuberculin antigen (Ag), constitute a routine exam to detect active or latent TB | Cheap & easy but low sensitivity and specificity—not reliable if it’s the only test and tricky to interpret |
Thoracic radiography | Detection of the pathognomonic changes, able to detect latent TB | On site but low sensibility and only for pulmonary tuberculosis |
PCR/GeneXpert® | Detection of the DNA of mycobacterium, able to detect active TB but also exposure to TB. It can confirm a case | Reliable if clinical signs present but expensive & only for active TB |
ELISA/Quantiferon TB Gold Plus® | Detection of the antibody (Ab) present, able to detect latent or active TB | Able to detect latent form but frequent crossed reactions & expensive test |
Microscopy—ZN staining | Detection of the bacillus, able to detect active TB | Easy, feasible on site but low sensitivity & specificity |