Comparison between a whole blood interferon-gamma release assay and tuberculin skin testing for the detection of tuberculosis infection among patients at risk for tuberculosis exposure.
A new test that measures interferon-gamma (IFN-gamma) release in whole blood following stimulation with tuberculin has the potential to detect tuberculosis infection using a single blood draw. The IFN-gamma release assay was compared with the standard tuberculin skin test (TST) among 467 intravenous drug users at risk for tuberculosis in urban Baltimore. Among 300 human immunodeficiency virus (HIV)-seronegative patients, the IFN-gamma release assay was positive in 177 (59%), whereas the TST was positive in 71 (24%), for a percent agreement of 59% (kappa=26%). Among 167 HIV-seropositive subjects, the IFN-gamma release assay identified 32 reactors (19%); the TST identified 16 reactors (9.6%), for a percent agreement of 82% (kappa=28%). The IFN-gamma release assay detected more reactors than did the TST, but its agreement with TST was weak. As the TST is an imperfect standard, further evaluation of the IFN-gamma release assay among uninfected persons and persons with culture-confirmed tuberculosis will be useful.
Kimura
M
M
Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA. mkimura@jhsph.edu
Converse
P J
PJ
Astemborski
J
J
Rothel
J S
JS
Vlahov
D
D
Comstock
G W
GW
Graham
N M
NM
Chaisson
R E
RE
Bishai
W R
WR
D005069:Evaluation Studies as Topic; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000150:complications*; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D008137:Longitudinal Studies; D015819:Substance Abuse, Intravenous / Q000150:complications*; D014373:Tuberculin; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis*
D014373:Tuberculin; D007371:Interferon-gamma