Eisenhut M(1), Fidler K(2).
Objectives. International
guidelines differ in the threshold of tuberculin skin test (TST) induration
regarded as indicating Mycobacterium (M.) tuberculosis infection. Interferon
gamma release assay (IGRA) results were used as reference to assess performance
of TST induration thresholds for detection of M. tuberculosis infection in
children.
Design. Systematic review
which included studies containing data on TST, IGRA, and Bacillus
Calmette-Guérin (BCG) status in children. Data bases searched were PubMed,
EMBASE, and the Cochrane library. Specificities and sensitivities were
calculated for TST thresholds 5, 10, and 15 mm and correlated with age and
geographical latitude.
Results. Eleven studies with
2796 children were included. For BCG immunised children diameters of 5, 10, and
15 mm had median sensitivities of 87, 70, and 75% and specificities of 67, 93,
and 90%, respectively. In non-BCG immunised children median sensitivities were
94, 95, and 83% and specificities 91, 95, and 97%. At the 10 mm threshold age
correlated negatively with sensitivity of TST (r = -0.65, P = 0.04) and latitude
correlated positively (r = 0.71, P = 0.02).
Conclusions. For the 10 mm threshold
the sensitivity of the TST is lower in BCG immunised children. Younger age and higher geographical latitude were
associated with higher sensitivity of the TST.
