TB skin testing (TST) is a useful tool for diagnosing inactive tuberculosis. The test is not as helpful in the diagnosis of active TB and can produce a ‘false negative’ result in some patients with advanced disease and/or who are immunocompromised. For more information about TB skin tests, please view the Middlesex-London Health Unit’s TB skin testing Information Sheet (PDF 69KB).
Two Interferon Gamma Release Assays (IGRAs) are licensed for use in Canada: Quantiferon TB Gold and T-SPOT TB. Currently, these tests are not covered under the Ontario Health Insurance Plan (OHIP). Quantiferon TB Gold testing can be obtained on a limited basis through Gamma-Dynacare Medical Laboratories. The cost for this testing is approximately $90.00.