Tuberculosis (TB) is a disease caused by bacteria that primarily affects the lungs and can be spread through an infected person’s breath, especially through coughing or speaking. Symptoms include respiratory distress, organ failure and eventual death, but is curable when caught and treated early. Many people infected with TB bacteria experience a symptomless, inactive stage of infection. This stage is known as “latent tuberculosis infection” (LTBI). Screening for – and treating people with – LTBI can reduce the risk of symptoms appearing and spreading TB to others.

The interferon-gamma release assay (IGRA) can determine if an individual has been exposed to the bacteria that causes TB. This technology involves testing a blood sample for an immune system response in a laboratory. Currently in Ontario, only the tuberculin skin test (TST) is publicly funded as a test for LTBI. The IGRA test is considered an acceptable alternative to the TST for people who may have LTBI by the Canadian Tuberculosis Standards, published in 2022.

This health technology assessment looked at how accurate and cost-effective IGRA testing is for LTBI. It also evaluates the budget impact of publicly funding IGRA. We reached out to people with LTBI to learn about their experiences, preferences, and values, but were unable to complete interviews. Instead, we spoke to 53 health care providers who order and rely on the results of TB tests.