Role of interferon-gamma release assays in healthcare workers

Safety of the two-step tuberculin skin test in Indian health care workers

“…Furthermore, IGRAs are in vitro tests and eliminate concerns regarding adverse events or boosting and do not require a return visit [1,8,[16][17][18]. The use of IGRAs for HCWs is increasing and there are several published studies and two systematic reviews published [8,[19][20][21]. While these assays show promise for screening in low incidence settings, they appear to have a lower sensitivity in high incidence settings such as India [8,16,19].…”

Screening for Mycobacterium tuberculosis Using an Interferon-Gamma Release Assay

“…IGRAs have shown poor agreement with TSTs, but greater concordance with TB exposure in health care workers from countries with low TB burden. 13,14 A study of conversion rates over time in those screened with IGRAs would contribute to knowledge about strategies for prevention and control in health care as well as public service settings. In addition to surveillance, the CDC guidelines 9 also recommend using IGRAs to identify persons most likely to benefit from treatment to prevent the progression of latent TB infection to active TB disease.…”

Immediate Incubation Reduces Indeterminate Results for QuantiFERON-TB Gold In-Tube Assay

“…For the patient, an equivocal result can lead to repeat testing and even a workup for immunologic disease with concomitant uncertainty and inconvenience. In the case of a latent TB diagnosis, repeated equivocal results and/or discrepancies between QFT and TST results create diagnostic challenges for the provider, and there is no consensus on how to resolve them (14), particularly with regard to whether to initiate prophylaxis with isoniazid, a therapy with known toxic side effects. Further, repeated testing, additional diagnostic evaluation, and over-or undertreatment all add to health care costs and reduce efficiency.…”

“…Prophylactic treatment of individuals with latent infection is an effective strategy to prevent progression to active disease and further spread (9). After more than a century of using the tuberculin skin test (TST) for diagnosis of latent tuberculosis infection (LTBI), the development of T-cell-based gamma interferon (IFN-␥) release assays (IGRAs) represents a significant advancement in the field of tuberculosis (TB) diagnostics (1,14). These assays rely on the measurement of increased IFN-␥ secretion by effector T cells which have previously been exposed to M. tuberculosis antigens (Ags) from an infection when the cells are stimulated in vitro with purified M. tuberculosis-specific antigens, such as the early secretory antigen 6 (ESAT-6) and culture filtrate protein 10 complex (CFP-10) (2).…”