Download Client Notice – Improved Testing for TB Infection

CLIENT NOTICE
Improved Testing for TB Infection
May 2013
Gamma-Dynacare is pleased to offer an innovative and convenient Health Canada-approved blood test for use in the diagnosis of
Mycobacterium tuberculosis (TB) infection. The test provides greater sensitivity (84.5% vs. 71.5%) and specificity (99.2% vs.
78.0%) than the century-old tuberculin skin test (TST), especially for those patients with previous BCG vaccination.
QuantiFeron®-TB Gold (QFT) is a blood test that measures the amount of interferon-gamma that is released when the infected white
blood cells come into contact with specific antigens for Mycobacterium tuberculosis. This new Interferon-Gamma Release Assay (IGRA)
methodology offers a modern alternative to the tuberculin skin test (TST), and has seen growing support in guidelines and
recommendations from reputed agencies, such as the Centers for Disease Control and Prevention (CDC), the American College of
Rheumatology and the Infectious Diseases Society of America.
Results are reported both qualitatively (positive or negative test result) and quantitatively (numerical value). The higher specificity and
sensitivity of the QFT provides more confidence in the detection of infected patients who may have been missed by the TST. CDC
recommends QFT over the TST because (a) a positive QFT result is almost 100% specific for M. tuberculosis infection; (b) QFT results
are unaffected by previous BCG vaccination or by infection with most other environmental mycobacteriae; (c) QFT requires only one
patient visit vs. TST, which requires two, possibly four visits; and (d) QFT does not affect subsequent test results (as has been observed
in TST two-step testing). In addition, QFT is less subject to TST reader bias and has less possibility of reactivity with non-Tuberculosis
mycobacteriaceae.
QFT is approved by both the FDA and Health Canada as “an in vitro diagnostic aid for detection of Mycobacterium tuberculosis
infection”. Studies have also suggested the value of QFT in identifying people who will progress to active TB disease. However, as with
any laboratory test, interpretation should always be combined with proper assessment of the patient, taking into consideration medical
history, physical examination and other test results in order to diagnose latent infection or active disease.
The QuantiFeron®-TB Gold (QFT) uses a special blood collection and is available at 14 of our Patient Service Centres which are listed
on the reverse side of this Notice. No appointment is necessary. The test may be ordered on the OHIP requisition.
If you have any questions or comments, please contact Peter Kornherr, Technical Specialist, Microbiology at 1-866-790-3515 ext. 6404
or by e-mail at [email protected]. References:
1.
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3.
4.
5.
6.
7.
8.
Mazurek, G.H. et al. (2010) MMWR. . Centers for Disease Control and Prevention. Updated Guidelines for Using Interferon Gamma Release Assays to Detect
Mycobacterium tuberculosis Infection – United States
Singh, J.A. et al. (2102) 2012 Update of the 2008 American College of Rheumatology Recommendation for the Use of Disease-Modifying Antirheumatic Drugs
and Biologic Agents in the treatment of Rheumatoid Arthritis. Arthritis, Care & Research 64, 5
Aberg, J.A. et al. (2009) Primary Care Guidelines for the Management of Persons Infected with Human Immunodeficiency virus: 2009 Update by the HIV
Medicine Association of the Infectious Diseases Society of America. Clinical Infectious Diseases. 49, 651
Diel et al.(2010). Evidence-Based Comparison of Commercial Interferon-γ Release Assays for Detecting Active TB: A Metaanalysis. Chest 137(4), 952
Pai et al.(2008). Systematic Review: T-cell-based Assays for the Diagnosis of Latent Tuberculosis Infection: An Update. Ann Intern Med. 149:177
Diel et al.(2011). Negative and Positive Predictive Value of a Whole-Blood Interferon-γ Release Assay for Developing Active Tuberculosis: An Update. Am J
Respir Crit Care Med. 183, 88.
Haguchi et al. (2008). Relatonship Between Whole-Blood Interferon-Gamma Responses and the Risk of Active Tuberculosis. Tuberculosis 88,244
QuantiFERON-TB Gold In-Tube Package Insert; reviewed and approved by the FDA. www.cellestis.com.
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Patient Services Centres that offer QuantiFeron®-TB Gold testing
Hours of operation are Monday to Friday
unless otherwise indicated
Location
Brampton
10 Cottrelle Blvd, Unit 108
Hamilton
849 Upper Wentworth, Suite 100
Kingston
190 Wellington St., Suite 201
London
245 Pall Mall St.
Markham
110 Copper Creek Dr., Unit 104
Mississauga
2000 Credit Valley Rd., Suite 107
Ottawa
750 Peter Morand Cres.
150 Montreal Rd., Suite 100
Peterborough
26 Hospital Dr.
Richmond Hill
328 Hwy #7 E., #210
Scarborough
3030 Lawrence Ave. E., Suite B05
4040 Finch Ave. E., #LL5
Toronto
123 Edward St., #808
Windsor
700 Tecumseh Rd East, Suite 8
Telephone
Hours of Operation
905-794-2227
8:00 a.m. - 4:00 p.m.
905-389-3122
7:00 a.m. - 5:00 p.m.
613-547-8133
8:00 a.m. - 1:00 p.m.
519-679-1630 ext. 1250
7:00 a.m. - 5:00 p.m.
905-294-3519
8:00 a.m. - 4:00 p.m.
905-828-1148
7:00 a.m. - 8:00 p.m.
613-729-0200 ext 6308
613-742-7627
7:30 a.m. - 3:00 p.m.
7:30 a.m. - 4:30 p.m.
705-876-7313
7:30 a.m. - 5:00 p.m.
905-881-4619
8:00 a.m. - 5:00 p.m.
416-438-3503
416-292-0222
8:00 a.m. - 5:00 p.m.
8:00 a.m. - 8:00 p.m.
416-597-0333
8:00 a.m. - 5:00 p.m.
519-252-3457
7:30 a.m. - 5:00 p.m.
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