All people, except infants aged <6 months, are recommended to receive a tuberculin skin test (TST; Mantoux) before BCG vaccination

All people, except infants <6 months of age, should have a tuberculin skin test (TST; Mantoux) before BCG vaccination. Only immunocompetent people who have induration of <5 mm after a TST should receive BCG vaccine.

The TST uses a tuberculin purified protein derivative. This causes a hypersensitivity reaction in people who have a Mycobacterium tuberculosis infection. Hypersensitivity reactions can also occur in:

• people who are infected with other mycobacteria
• people who have previously received BCG vaccine

Health professionals must correctly administer and interpret the TST. Consult state or territory tuberculosis guidelines for advice.

The measles virus inhibits the response to tuberculin. Tuberculin-positive people may become tuberculin-negative for 4–6 weeks after measles infection, and measles-containing vaccines have a similar effect. ^6,7

Because of this, the TST may be unreliable for at least 4–6 weeks in people who have received a measles-containing vaccine.

Interferon-gamma release assays (IGRAs) are a type of blood test that can detect M. tuberculosis infection, but the TST is still the preferred method of screening for tuberculosis, unless the person has previously received BCG vaccine.⁸