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