Interferon-γ release assays in tuberculosis contacts: is there a window period?

Anibarro, Luis; Trigo, María Del; Villaverde, C.; Peña, Alberto; Cortizo, S.; Sande, Denise; Pazos, Rodolfo Andrés Villarreal; González-Fernández, África

doi:10.1183/09031936.00030610

Cited by 30 publications

(19 citation statements)

References 10 publications

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“…The IGRA tests were used instead of the tuberculin skin test to exclude the influence of Bacille Calmette-Guérin vaccination or non-tuberculous mycobacteria [25] and contacts were tested with both IGRAs, T-SPOT.TB and QFT IGRAs, to avoid possible false-negative results when either method is used alone. Since the window period for IGRAs to become positive after exposure has not been clearly defined [26], the third IGRA was performed on the contacts after a 3-month interval.…”

Section: Discussionmentioning

confidence: 99%

An office building outbreak: the changing epidemiology of tuberculosis in Shenzhen, China

et al. 2020

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Tuberculosis (TB) is generally considered a disease that principally afflicts the low-income segments of a population. In the Nanshan District of Shenzhen, China, with the economic transformation and a new Headquarters Economy (HE) emerging, there are now more cases in office workers than in manufacturing workers. To illustrate this trend, we describe a small TB outbreak in an office building located in the centre of the rapidly growing HE district. Two active pulmonary tuberculosis cases were found in workers who shared an office, and whole genome sequencing showed that the genetic distance between the strains of the two cases was just one single nucleotide polymorphism, consistent with intra-office transmission. Investigation of 30 other workers in the same or adjacent offices with interviews, interferon-gamma release assays (IGRAs) and chest X-rays, identified one new TB case and latent tuberculosis infection (LTBI) in 40.0% (12/30) of the contacts. The offices were under-ventilated. None of the IGRA positive, asymptomatic contacts agreed to receive treatment for LTBI, presumably due to TB stigma, and over the next 2 years 69.0% (20/29) of the contacts were lost to follow-up. Treatment for LTBI and stigma of TB remain challenges here. Office workers in the HE of rapidly economic developing areas should be targeted with increased vigilance by TB control programmes.

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Section: Discussionmentioning

confidence: 99%

An office building outbreak: the changing epidemiology of tuberculosis in Shenzhen, China

et al. 2020

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“…A negative TST obtained < eight weeks before does not exclude infection, and a second test is recommended after eight weeks. [12] Also, because it may take longer than 72 h for an elderly individual to develop a reaction, it may be useful to repeat the TB skin test after 96 h and again at one week to adequately screen these individuals. Immunocompromised persons may be unable to react sufficiently to the Mantoux test, and either a chest X-ray or sputum sample may be required.…”

Section: Interpretation Of Tuberculin Reactionmentioning

confidence: 99%

Mantoux test and its interpretation

Nayak

Acharjya

2012

Indian Dermatol Online J

166

120

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The tuberculin skin test is one of the few investigations dating from the 19th century that are still widely used as an important test for diagnosing tuberculosis. Though very commonly used by physicians worldwide its interpretation always remains difficult and controversial. Various factors like age, immunological status coexisting illness etc influence its outcome, so also its interpretation. Utmost care is required while interpreting the result and giving an opinion. This article has been written with the purpose of elucidating the performance and interpretation of the standard tuberculin test.

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“…Whereas the TST is known to convert in 2–12 weeks [ 11 , 12 ], the conversion interval for IGRA is not well established and may vary from 4–22 weeks [ 13 , 14 ]. Some studies have suggested that IGRA becomes positive before the TST [ 15 ] but others have not [ 13 ]. Secondly, recent evidence has shown problems with the reproducibility of IGRA results [ 4 ] and the related issue of IGRA reversions (from positive to negative) [ 16 – 21 ].…”

Section: Introductionmentioning

confidence: 99%

Cough Aerosol Cultures of Mycobacterium tuberculosis: Insights on TST / IGRA Discordance and Transmission Dynamics

et al. 2015

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RationaleThe diagnosis of latent tuberculosis (TB) infection (LTBI) is complicated by the absence of a gold standard. Discordance between tuberculin skin tests (TST) and interferon gamma release assays (IGRA) occurs in 10–20% of individuals, but the underlying mechanisms are poorly understood.MethodsWe analyzed data from a prospective household contact study that included cough aerosol culture results from index cases, environmental and contact factors. We assessed contacts for LTBI using TST and IGRA at baseline and six weeks. We examined TST/IGRA discordance in qualitative and quantitative analyses, and used multivariable logistic regression analysis with generalized estimating equations to analyze predictors of discordance.Measurements and ResultsWe included 96 TB patients and 384 contacts. Discordance decreased from 15% at baseline to 8% by six weeks. In adjusted analyses, discordance was related to less crowding (p = 0.004), non-cavitary disease (OR 1.41, 95% CI: 1.02–1.96; p = 0.03), and marginally with BCG vaccination in contacts (OR 1.40, 95% CI: 0.99–1.98, p = 0.06).ConclusionsWe observed significant individual variability and temporal dynamism in TST and IGRA results in household contacts of pulmonary TB cases. Discordance was associated with a less intense infectious exposure, and marginally associated with a BCG-mediated delay in IGRA conversion. Cough aerosols provide an additional dimension to the assessment of infectiousness and risk of infection in contacts.

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Interferon-γ release assays in tuberculosis contacts: is there a window period?

Cited by 30 publications

References 10 publications

An office building outbreak: the changing epidemiology of tuberculosis in Shenzhen, China

An office building outbreak: the changing epidemiology of tuberculosis in Shenzhen, China

Mantoux test and its interpretation

Cough Aerosol Cultures of Mycobacterium tuberculosis: Insights on TST / IGRA Discordance and Transmission Dynamics

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