Accuracy of the QuantiFERON-TB Gold in Tube for diagnosing tuberculosis in a young pediatric population previously vaccinated with Bacille Calmette-Guerin

Abstract

Objective: To evaluate the accuracy of an interferongamma release assay (QuantiFERON-TB Gold in Tube) for diagnosing Mycobacterium tuberculosis infection in a young pediatric population. Methods: 195 children previously vaccinated with BCG were evaluated, being 184 healthy individuals with no clinical or epidemiological evidence of mycobacterial infection, and 11 with Mycobacterium tuberculosis infection, according to clinical, radiological, and laboratory parameters. A blood sample was obtained from each child and processed according to the manufacturer's instructions. The assay performance was evaluated by a Receiver Operating Characteristic (ROC) curve. Results: In the group of 184 non-infected children, 130 (70.6%) were under the age of four years (mean age of 35 months). In this group, 177 children (96.2%) had negative test results, six (3.2%) had indeterminate results, and one (0.5%) had a positive result. In the group of 11 infected children, the mean age was 58.5 months, and two of them (18%) had negative results. The ROC curve had an area under the curve of 0.88 (95%CI 0.82-0.92; p<0.001), disclosing a predictive positive value of 81.8% for the test (95%CI 46.3-97.4). The assay sensitivity was 81.8% (95%CI 48.2-97.2) and the specificity was 98.8% (95%CI 96-99.8). Conclusions: In the present study, the QuantiFERON-TB Gold in Tube performance for diagnosing M. tuberculosis infection was appropriate in a young pediatric population.

Evaluation of QuantiFERON tuberculosis Gold In‐Tube assay for diagnosis of active tuberculosis in children

“…However, in our study, QFT‐GIT showed no significant difference in terms of sensitivity in patients younger than 5 years of age. There are several reports in the literature to support our finding that the sensitivity of QFT‐GIT is not affected by age, and QFT‐GIT is a useful tool in the diagnosis of TB even in infants . Moreover, neither mitogen nor TB antigen response was lower in this age group, which supports the finding that the immune system of children under 5 years of age is mature enough to use QFT‐GIT.…”

“…As a result, accurate detection of MTB infection in children under 5 years of age has a crucial role . It is assumed that the performance of IGRAs in those younger than 5 years of age was poor mainly because of an immature immune system . However, in our study, QFT‐GIT showed no significant difference in terms of sensitivity in patients younger than 5 years of age.…”

“…Studies with a small sample that evaluated the performance of QFT‐GIT in definite paediatric TB cases reported sensitivities of QFT‐GIT between 65 and 100% . TST was reported to be more sensitive than QFT‐GIT (82–100%) in most of the studies .…”

“…QFT‐GIT performance also showed no difference in age‐dependent analysis. Poor response to mitogen and TB antigen at younger ages were detected in studies that mainly used QFT‐G . In the QFT‐GIT test, T‐cell stimulation was carried out in antigen‐coated tubes.…”

Comparação entre a prova tuberculínica e a detecção dos níveis de interferon-gama no diagnóstico da tuberculose latente em receptores de transplante de células-tronco hematopoiéticas

“…das demais infecções ocasionadas por outras micobactérias. Sendo assim, esta técnica foi logo abandonada 51,54,56,57. Avanços nos estudos do genoma das micobactérias, iniciados ainda na década de 90, resultaram na descoberta de duas proteínas exclusivas da membrana do MTB, propiciando assim, uma segunda geração destes testes.…”