Contact tracing occurs as soon as possible after identification of a new TB case:

*the source case is sought for, when an individual presents with non-infectious TB (centripetal);

*having a smear positive individual as a source case, potentially infected contacts are sought for (centrifugal).

Contact tracing in industrialized countries:

*the tuberculin test in younger individuals ( < 45 years) and non-BCG vaccinated;

*CXR in individuals > 45 years / BCG vaccinated / with a known positive tuberculin test.