With an urgent need to diagnose and treat those infected, the global TB diagnostic market is estimated to surpass $2 billion. This includes both active and latent testing, as well as dollars focused in developing nations addressing active and drug resistant TB.
More than 100 million tests are given annually to individuals in high exposure occupations requiring recurring TB screening. That number is expected to grow, with identification of newly infected contacts as top priority as the risk of infection is high and new infection carries a much greater risk of disease progression. Market growth drivers include globalization of citizenship, growth in high exposure occupations, newly available pharmaceutical treatments which require TB screening and accurate diagnosis, and cost avoidance for treatment due to misdiagnosis.
Current screening tools include the century old tuberculin skin test (TST), blood-based interferon-gamma (IFN-γ) release assays (IGRA), and chest X-ray. The market does not consider any of these tests to be gold standard and none differentiate between active and latent TB.
The market leader remains TST, in spite of a 20% error rate (false positive and general lack of quality control), test antigen unavailability, time to result, and second-visit patient non-compliance. Two IGRA assays were introduced in 2008, and both are based on the single biomarker IFN-ɣ.
Since commercialization of the IGRA assays, multiple studies have indicated confounding results, particularly high false positive rates (>10%), even among low incidence populations. Failure of the currently available IGRAs to accurately diagnose TB infection has caused some countries to limit and/or ban its use.