TABLE 2.

Canadian tuberculosis standards: interpretation of tuberculin test

Tuberculin reaction (induration [mm])	Setting in which reaction was considered significant (meaning probable tuberculosis infection)
0–4	Human immunodeficiency virus infection and/or expected risk of tuberculosis infection is high (eg, patient is an immigrant from a country where tuberculosis is endemic, is a household contact, or has an abnormal radiograph). This reaction size is not normally considered significant, but in the presence of immune suppression may be important
5–9	Human immunodeficiency virus infection
	Close contact of active contagious case
	Abnormal chest radiograph with fibronodular disease
10	All others

Data from reference 28