Concordancia de las pruebas de tuberculina e Interferón gamma en población reclusa

Abstract

Objective: To study the agreement of Tuberculin Skin Tests (TST) and Interferon Gamma Release Assays (IGRA) when screening tuberculosis infection amongst inmates recently admitted to prison. Materials and Methods:Prospective study conducted in a prison during the months of May and June 2009. Inmates without a TB history, with previous TST negatives or without prior TSTs were included. Participants signed an informed consent form and the study was approved by an independent Ethical Committee. TST (positive 10 >= mm) and IGRA (Quantiferon TB-Gold) were performed and standardized data collection was carried out. The agreement between both tests was analyzed using the Kappa index. Results: A total of 181 people were included. 62% were foreign-born, 17% had previous BCG vaccination; 8.4% were IDUs and 4% HIV-infected. Foreign born subjects were more frequently vaccinated and presented less drug use and HIV infection than people born in Spain. (p=0.02, p=0.02 and p=0.01 respectively). TST results were positive in 24% and IGRA in 26%. Both tests were performed in 149 people (82%). Discordant results were observed in 15.8%. Agreement of the Kappa coefficient was 0.6 (CI 0.4-0.7). Agreement was better in the native population (K=0.8) and worse in BCG vaccinated (K=0.4) and foreign-born subjects (K=0.8). Conclusion:Overall agreement was moderate and was less amongst vaccinated subjects and those born abroad. Extension of the study could be useful to evaluate which test better predicts the risk of progression to active TB and the cost-benefit of both tests among the prison population.

High prevalence and risk factors associated with latent tuberculous infection in two Colombian prisons

“…3 In our study, two risk factors were associated with the prevalence of positive TST: previous incarceration and length of detention; this is in line with previous studies. 20,21 In contrast to our results, prevalence of TST positivity reported in high-income countries is lower: 26.8% in Spain, 22 17.9% in Italy, 20 12-14% in Australia, 13 18% in the United States, 3 and 46.9% in Switzerland. 23 In low-middle-income countries, TST prevalence ranges between 48% in Pakistan, 24 52.4% in Nigeria, 25 60.8% in Brazil 26 and 88.8% in Malaysia.…”

Tuberculin Skin Testing versus Interferon-Gamma Release Assay among Users of a Public Health Unit in Northeast Portugal

“…Interestingly, IGRA positivity was less likely among immunized people, in accordance with previous research suggesting the relevance of the IGRA screening test in LTBI evaluation [12,19]. The higher specificity of IGRA to detect M. tuberculosis infection [29] and the protective effect of BCG vaccination on M. tuberculosis infection [12] could explain our results.…”

“…However, according to a recent systematic review, the prevalence of LTBI among HCW by using IGRA in low-incidence countries was only 16% [27]. Also, the proportion of LTBI we found among TB contacts and inmates was higher than reported in other European settings [4, 14, 28, 29]. Our findings probably reflect the TB burden in Portugal, a country with one of the highest incidence rates (20.5 new cases and relapses of TB per 100,000 population) and with one of the lowest TB treatment success rates (37.3%) among European countries in 2018 [23].…”

Prevalence of tuberculosis symptoms and latent tuberculous infection among prisoners in northeastern Malaysia

“…Although much debate remains about the utility of TST in bacille Calmette-Guérin (BCG) vaccinated populations, the immunogenic effects of BCG wane after 8–10 years. 19 While numerous studies have shown that the majority of TST-positive, interferon-gamma release assay-negative discordances occur in BCG-vaccinated populations, 20,21 these are relatively infrequent. The WHO therefore supports the use of TST to detect LTBI in settings where BCG is used.…”