Questionable effectiveness of the QuantiFERON-TB Gold Test (Cellestis) as a screening tool in healthcare workers.
OBJECTIVE
The Center for Disease Control and Prevention recommends the use of QuantiFERON TB Gold test (QFTG; Cellestis) in all situations where the tuberculin skin test (TST) is used. In November 2007, our institution replaced its screening-tool TST with the QFTG in-tube assay (QFT-GIT) for annual screening of latent tuberculosis infection among healthcare workers (HCWs). This study evaluated the effectiveness of QFT-GIT test as screening tool in HCWs at our institution.


METHODS
This retrospective study reviewed medical records of all HCWs who underwent screening with QFT-GIT from January 2008 through December 2008.


RESULTS
Among the 6,530 HCWs screened with QFT-GIT from January through December 2008, 287 had a positive test result. Of the 287, 123 had positive TST results in the past, meaning that 164 HCWs had newly diagnosed latent tuberculosis infection by QFT-GIT. Of the 164 HCWs, 135 were retested by QFT-GIT and were simultaneously tested with TST within 4 weeks after the initial QFT-GIT. Of these 135 HCWs, 66 reverted to negative results and results remained positive for 69 with QFT-GIT. Only 2 HCWs had a positive TST result.


CONCLUSIONS
The disagreement between QFT-GIT and TST results and the high reversion rate with QFT-GIT raise concerns about the effectiveness of QFT-GIT as a sole screening test in HCWs.
Gandra
Sumanth
S
University of Illinois College of Medicine at Peoria, USA. gandrasatyam@gmail.com
Scott
William S
WS
Somaraju
Vijaya
V
Wang
Huaping
H
Wilton
Suzanne
S
Feigenbaum
Michelle
M
D000328:Adult; D002487:Centers for Disease Control and Prevention, U.S.; D004797:Enzyme-Linked Immunosorbent Assay / Q000191:economics / Q000379:methods* / Q000592:standards*; D005260:Female; D006282:Health Personnel; D006403:Hematologic Tests / Q000191:economics / Q000379:methods / Q000592:standards; D006801:Humans; D007087:Illinois; D007371:Interferon-gamma / Q000276:immunology; D055985:Latent Tuberculosis / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000302:isolation & purification; D009784:Occupational Diseases / Q000175:diagnosis / Q000191:economics; D011159:Population Surveillance / Q000379:methods*; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014481:United States
D007371:Interferon-gamma