QuantiFERON Gold & IGRA TB Test — Mississauga

QuantiFERON-TB Gold (QFT) is a blood test for tuberculosis (TB) infection — also called an IGRA (Interferon-Gamma Release Assay). Like the TB skin test (Mantoux/TST), it detects latent TB infection (TB bacteria present in the body but not causing active disease). The key difference: QuantiFERON requires only one blood draw and one visit; no return visit is needed to read results. The TB skin test requires two visits — the test is placed on day 1 and read at 48–72 hours. QuantiFERON is also not affected by BCG vaccination, which can cause false-positive skin tests in many immigrants.

QuantiFERON or IGRA testing is recommended for: immigration to Canada (as part of the medical exam requirement for many countries); healthcare workers as part of baseline and annual occupational screening; people who have spent significant time in high TB-burden countries; people with recent known TB exposure; people starting immunosuppressive medications (biologics, steroids, TNF inhibitors) who need TB clearance; and anyone who has a positive skin test but was BCG-vaccinated (to confirm true vs false positive).

In most situations, yes — QuantiFERON is an accepted alternative to the TB skin test for latent TB screening. The Public Health Agency of Canada and most institutions accept either test. QuantiFERON is preferred for people who received BCG vaccine (common in India, Pakistan, Philippines, Africa, and many other countries) because BCG vaccination frequently causes false-positive skin test results. Your employer, school, or immigration authority will specify which test they accept — confirm before booking.

Blood is drawn at our clinic and sent to the laboratory. Results are typically available within 3–5 business days. We will notify you when results are ready. If you need results urgently (for an upcoming immigration appointment or employment start date), let us know and we will do our best to expedite processing.

A positive QuantiFERON result indicates latent TB infection — meaning TB bacteria are present in your body but you do not have active TB disease. Latent TB is not contagious and usually causes no symptoms. Treatment for latent TB (preventive therapy) may be recommended to prevent it from becoming active TB disease in the future. Our physician will discuss your options, which typically involve a 9-month course of isoniazid or a shorter rifampin-based regimen. A positive IGRA requires follow-up with a chest X-ray to rule out active TB.

QuantiFERON-TB Gold testing is not covered by OHIP in most circumstances and is typically an out-of-pocket expense. Some employers, particularly in healthcare, cover the cost as part of occupational health requirements. Immigration-related TB testing is generally not OHIP-covered. The TB skin test (Mantoux/TST) has similar coverage. We provide official receipts for all testing for insurance or employer reimbursement purposes. Contact your benefits provider to confirm coverage before your appointment.