Use of the QuantiFERON-TB Gold test to confirm latent tuberculosis infection in a Canadian tuberculosis clinic.
METHODS
Capital Health Tuberculosis (TB) Clinic, Edmonton, Alberta, Canada.


OBJECTIVE
To analyze the QuantiFERON-TB Gold In-Tube test (QFT) results after implementation as a routine test for tuberculin skin test (TST) positive patients.


METHODS
From November 2004 until January 2007, patients who were TST-positive and were eligible for preventive treatment based on Canadian guidelines, were offered a QFT.


RESULTS
Of 1446 TST-positive patients, only 566 (39.6%) were QFT-positive. Categorized by reason for TST testing, 43.1% of 304 contacts, 32.8% of 348 employment screens and 24.2% of 298 post secondary school screens were QFT-positive. In contrast, 59.7% of 290 immigration screens were QFT-positive. A multivariate analysis found that QFT positivity was associated with older age, larger TST size, high-incidence TB region of birth, history of TB and chest X-ray findings suggestive of previous TB.


CONCLUSIONS
Implementation of the QFT as a secondary test for latent TB infection (LTBI) can significantly reduce the number of patients given LTBI treatment in a low-incidence country such as Canada.
Kunimoto
Dennis
D
Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. Dennis.Kunimoto@ualberta.ca
Der
E
E
Beckon
A
A
Thomas
L
L
Egedahl
M
M
Beatch
A
A
Williams
G
G
Tyrrell
G
G
Ahmed
R
R
Brown
N
N
Long
R
R
D000328:Adult; D000367:Age Factors; D000368:Aged; D000416:Alberta / Q000453:epidemiology; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D008875:Middle Aged; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012307:Risk Factors; D014374:Tuberculin Test / Q000379:methods* / Q000706:statistics & numerical data; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology; D055815:Young Adult
D011933:Reagent Kits, Diagnostic