Comparison of two commercial interferon-gamma assays for diagnosing Mycobacterium tuberculosis infection.
The clinical usefulness of ex vivo interferon-gamma assays may largely depend on the assay format and epidemiological status of tuberculosis (TB) in the region studied. From July 2004 to June 2005 a prospective comparison study was undertaken at a tertiary referral hospital in South Korea. The results of tuberculin skin tests (TST) and the commercially available QuantiFERON-TB Gold (QFT-G) and T SPOT-TB (SPOT) assays were compared in an intermediate TB-burden country. Of the 224 participants studied, results from all three tests (TST, QFT-G, and SPOT) were available in 218; 87 with active TB and 131 at a low risk for TB. Using 10 mm as a cut-off for TST, SPOT sensitivity (96.6%) was significantly higher than that seen for TST (66.7%) and QFT-G (70.1%). QFT-G showed superior specificity over TST (91.6 versus 78.6%). Although the specificity of QFT-G was higher than that of SPOT (91.6 versus 84.7%), the difference was not statistically significant. Whilst some differences were found in the performance of the two commercialised interferon-gamma assays, they seemed to be superior in their detection of Mycobacterium tuberculosis infection compared with tuberculin skin tests. The most appropriate choice of interferon-gamma assay to use may depend on the clinical setting.
Lee
J Y
JY
Division of Pulmonary and Critical Care Medicine, Dept of Internal Medicine, Asan Medical Center, College of Medicine University of Ulsan, 388-1 Pungnap-2dong, Songpa-gu, Seoul 138-736, South Korea.
Choi
H J
HJ
Park
I-N
IN
Hong
S-B
SB
Oh
Y-M
YM
Lim
C-M
CM
Lee
S D
SD
Koh
Y
Y
Kim
W S
WS
Kim
D S
DS
Kim
W D
WD
Shim
T S
TS
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000378:metabolism; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000378:metabolism
D000942:Antigens, Bacterial; D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma