A technician performs a Mantoux tuberculin test (named after its creator, French physician Charles Mantoux), which is used to evaluate people for latent tuberculosis infection. The injection causes a 6–10 mm (0.24–0.39 in) wheal (bump) and the test is evaluated by measuring the diameter of the induration (hardening of the skin) at the injection site a few days later.Photo: Greg Knobloch, CDC