To date, the criteria for a positive TBST have been established by the manufacturers. These criteria are based on clinical data in relatively small numbers of patients. In addition, all of the studies to date evaluating accuracy of these tests have used cross-sectional designs. Data from prospective observational or experimental studies may result in modification of these criteria in the future.
Table 3.2. Criteria for a positive TBST
TBST: Mycobacterium tuberculosis antigen-based skin test.
ᵃThe criteria are all taken from manufacturers product inserts (37, 40, 41).
ᵇAll responses are considered positive according to the package insert.