6
Diagnosis
Figure 2. Summary of Recommendations for Testing for LTBI
Group Testing Strategy Considerations
Likely to be Infected
High Risk of
Progression
(TST ≥5 mM)
Adults:
Acceptable: IGRA or TST
Consider dual testing where a positive
result from either result would be
considered positive
Children ≤5 years of age:
Preferred: TST
Acceptable: IGRA or TST
Consider dual testing where a
positive result from either would be
considered positive
a
• Prevalence of
BCG vaccination
• Expertise of staff
and/or laboratory
• Test availability
• Patient
perceptions
• Staff perceptions
• Programmatic
concerns
Likely to be Infected
Low to Intermediate
Risk of Progression
(TST ≥10 mM)
Preferred: IGRA where available
Acceptable: IGRA or TST
Unlikely to be Infected
(TST >15 mM)
Testing for LTBI is NOT
recommended
If necessary:
Preferred: IGRA where available.
Acceptable: Either IGRA or TST
For serial testing:
Acceptable: Either IGRA or TST
Consider repeat or dual testing where
a negative result from either would be
considered negative
b
a
Performing a second diagnostic test when the initial test is negative is a strateg y to increase
sensitivity. is may reduce specificity, but the panel decided that this is an acceptable trade-off in
situations in which the consequences of missing LTBI (ie, not treating individuals who may benefit
from therapy) exceed the consequences of inappropriate therapy (ie, hepatotoxicity).
b
Performing a confirmatory test following an initial positive result is based upon both the evidence
that false-positive results are common among individuals who are unlikely to be infected with Mtb
and the committee's presumption that performing a second test on those patients whose initial test
was positive will help identify initial false-positive results.
