QuantiFERON-TB Gold In-Tube Test Research Articles

Interferon Gamma-Based Detection of Latent Tuberculosis Infection in the Border States of Nuevo Leon and Tamaulipas, Mexico.

Nearly one-third of the world’s population is infected with latent tuberculosis (LTBI). Tuberculosis (TB) rates in the border states are higher than national rates in both the US and Mexico, with the border accounting for 30% of total registered TB cases in both countries. However, LTBI rates in the general population in Mexican border states are unknown. In this region, LTBI is diagnosed using the tuberculin skin test (TST). New methods of detection more specific than TST have been developed, although there is currently no gold standard for LTBI detection. Our objective is to demonstrate utility of the Quantiferon TB gold In-Tube (QFT-GIT) test compared with the TST to detect LTBI among border populations. This is an observational, cross-sectional study carried out in border areas of the states of Nuevo Leon and Tamaulipas, Mexico. Participants (n = 210) provided a TST and blood sample for the QFT-GIT. Kappa coefficients assessed the agreement between TST and QFT-GIT. Participant characteristics were compared using Fisher exact tests. Thirty-eight percent of participants were diagnosed with LTBI by QFT-GIT. The proportion of LTBI detected using QFT-GIT was almost double [38% (79/210)] that found by TST [19% (39/210)] (P < 0.001). Concordance between TST and QFT-GIT was low (kappa = 0.37). We recommend further studies utilizing the QFT-GIT test to detect LTBI among border populations.

Serial interferon-gamma release assays for latent tuberculosis in dialysis patients with end stage renal disease in a Korean population.

BackgroundSerial interferon-gamma-release-assay (IGRA) result can show variance due to within-subject variation and difference in host immune status, and may be affected by latent tuberculosis infection (LTBI) treatment. We aimed to know the changes in QFT-IT (QuantiFERON-TB Gold In-Tube) results measured at a 4 month interval in end stage renal disease patients and whether these changes were influenced by dialysis method or LTBI treatment.MethodsWe prospectively performed serial QFT-IT tests at 4 month interval in 93 end stage renal disease (ESRD) patients on HD (hemodialysis) or PD (peritoneal dialysis). LTBI treatment was given to 18 of 39 patients with initial positive QFT-IT result. Agreement between the two results was estimated for all 93 patients and reversion rates were estimated among the 39 patients with initial positive QFT-IT.ResultsPositive QFT-IT at the first and 2nd tests were 41.9 and 34.4 %, respectively. The concordance rate between baseline QFT-IT and 2nd QFT in 93 ESRD patients was excellent (90.3 %, kappa = 0.80, p < 0.001). Agreement between the first QFT-IT and 2nd QFT-IT in HD (95.3 %, kappa = 0.91, p < 0.001) was higher than in PD patients (86.0 %, kappa = 0.69, p < 0.001). Among all ESRD patients, the odds of reversion of QFT-IT was not different in those who were, or were not treated for LTBI [odds ratio = 2.3 (0.5–11.4), p = 0.43].ConclusionsIn a group of 93 dialyzed ESRD patients 8.6 % showed reversion of initial positive QFT to negative within 4 months. Reversion seemed not to be associated with LTBI treatment. Further study with larger numbers of patients is needed to investigate the variation of QFT-IT tests in dialyzed ESRD patients.

Comparison of tuberculin skin test and QuantiFERON®-TB Gold In-Tube for the diagnosis of childhood tuberculosis.

Tuberculosis (TB) is an important worldwide ongoing health issue. To be able to control TB, one should not only cure active TB but also identify childhood TB patients who have the possibility to develop active disease in the future. The aim of this study was to compare a century-old tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube (QFT-GIT) test, developed as an alternative to TST and which has been claimed to be superior to TST in several ways, in the diagnosis of childhood TB. Fifty-three children with TB between 5 months and 17.5 years of age and 92 healthy children from the same age group with no risk factors for TB were recruited into the study. All children underwent TST and QFT-GIT test and their demographic, clinic and laboratory data were recorded. Data were analyzed using SPSS 14. A total of 53 patients were diagnosed with TB. Mean patient age was 8.5 ± 4.3 years (range, 5 months-17.5 years). A total of 41.7% of the patients were female. Sixteen of 53 patients had confirmation on culture. QFT-GIT test was positive in 16 and TST was positive in 15 among 16 children with culture-confirmed TB. The sensitivity of TST and QFT-GIT were 93.8% and 100.0%, and the specificity of TST and QFT-GIT were 100.0% and 97.8%, respectively. With regard to the 53 TB children including those without bacteriological confirmation, QFT-GIT was positive in 33 children, and TST was positive in 44 children. The sensitivity of TST and QFT-GIT was then 83.0% and 62.3%, and the specificity, 100.0% and 97.8%, respectively. Although positive QFT-GIT test is very significant for TB, negative results will not exclude TB infection. TST and QFT-GIT used together may provide more efficient results.

Discordance Between Tuberculin Skin Test and Interferon-γ Release Assay in Children Younger Than 5 Years Who Have Been Vaccinated With Bacillus Calmette-Guérin.

Interferon-γ release assays (IGRAs) offer the possibility of improved detection of latent tuberculosis infection (LTBI). To analyze discordant tuberculin skin testing (TST) and IGRA results in ethnic Croatian children as old as 5 years for whom there is documented exposure to an adult with active tuberculosis (TB) and who have been vaccinated with Bacillus Calmette-Guérin. In specimens from our cohort individuals, we tested the performances of the QuantiFERON-TB Gold In-Tube (QFT-GIT) test and TST and analyzed discordant results. At the TST cutoff value of 10 mm or greater, the estimated prevalence of M. tuberculosis infection was 18.1% (31/171) using TST and 15.2% (26/171) using QFT-GIT. The results of these 2 tests showed an overall concordance of 87.7%. There was no evidence that subjects' age correlated with discordant results. The reasons for discordant results in young children are still unclear, which highlights the importance of further longitudinal studies to better understand the interpretation and any possible clinical implications of the results of these tests.

Predictive factors for treatment failure in patients with presumed ocular tuberculosis in an area of low endemic prevalence

AimTo assess the impact of antitubercular therapy (ATT), oral steroids and steroid sparing immunosuppressive treatment on treatment success in cases with presumed ocular tuberculosis in an area of low endemic...

Factors that Predict Negative Results of QuantiFERON-TB Gold In-Tube Test in Patients with Culture-Confirmed Tuberculosis: A Multicenter Retrospective Cohort Study.

BackgroundInterferon-γ release assays such as the QuantiFERON-TB Gold In-Tube Test (QFT-GIT) are designed to detect Mycobacterium tuberculosis infections, whether latent or manifesting as disease. However, a substantial number of persons with culture-confirmed tuberculosis (TB) have negative QFT-GITs. Information on host factors contributing to false-negative and indeterminate results are limited.MethodsA multicenter retrospective cohort study was performed with 1,264 culture-confirmed TB patients older than 18 years who were subjected to the QFT-GIT at one of the six hospitals between May 2007 and February 2014. Patients with human immunodeficiency virus infection were excluded. Clinical and laboratory data were collected in South Korea.ResultsOf all patients, 87.6% (1,107/1,264) were diagnosed with pulmonary TB and 12.4% (157/1,264) with extrapulmonary TB. The rate of negative results was 14.4% (182/1,264). The following factors were highly correlated with false-negative results in the QFT-GIT: advanced age (age ≥ 65 years, odds ratio [OR] 1.57, 95% confidence interval [CI] 1.03–2.39), bilateral disease as determined by chest radiography (OR 1.75, 95% CI 1.13–2.72), malignancy (OR 2.42, 95% CI 1.30–4.49), and lymphocytopenia (total lymphocyte count < 1.0 × 109/L, OR 1.86, 95% CI 1.21–2.87).ConclusionsConsequently, QFT-GIT results need to be interpreted with caution in patients with these host risk factors such as the elderly, bilateral disease on chest radiography, or malignancy, or lymphocytopenia.

Impact of tuberculosis treatment and antiretroviral therapy on serial RD-1-specific quantitative T-cell readouts (QuantiFERON-TB Gold In-Tube), and relationship to treatment-related outcomes and bacterial burden

The impact of anti-tuberculosis treatment with and without antiretroviral therapy (ART) on standardized interferon gamma release assay (IGRA) readouts has been studied inadequately in high-burden countries. The QuantiFERON-TB Gold In-Tube (QFT-GIT) test was used to evaluate interferon gamma (IFN-γ) responses longitudinally (0, 3, 6, and 12 months post initiation of tuberculosis (TB)-HIV co-treatment or ART alone) in 82 HIV-infected patients. Of the 65 evaluable participants, 30 were co-infected on ART, 17 were co-infected but not on ART, and 18 were HIV-infected alone and on ART. In HIV-infected and HIV-TB-infected patients on ART, IFN-γ responses increased, whilst they decreased in those not on ART. However, baseline, month 3, and month 6 IFN-γ responses, irrespective of ART, did not differ in TB-HIV co-infected patients who culture-converted compared to those who did not (1.25 vs. 1.05, p=0.5 at baseline; 3.76 vs. 1.15, p=0.2 for month 3; 0.06 vs. 0.7, p=0.3 for month 6). IFN-γ levels did not correlate with the magnitude of sputum bacillary load, smear status, or liquid culture time-to-positivity. As IGRAs do not correlate with 2- or 6-month culture conversion or with markers of bacillary burden, they are unlikely to be useful for the prognostication of treatment outcome in co-infected patients.

Post-treatment change in Mycobacterium tuberculosis antigen-stimulated tumor necrosis factor-alpha release in patients with active tuberculosis.

Monitoring tuberculosis (TB) treatment response remains challenging due to lack of reliable laboratory markers. In recent years, increased efforts have been exerted toward development of new biomarkers reflecting treatment response appropriately. While performance of interferon-gamma release assays (IGRAs) to monitor anti-TB treatment has been extensively evaluated, there is no data about post-treatment changes in Mycobacterium tuberculosis (MTB) antigen-stimulated tumor necrosis factor-alpha (TNF-α) release in active TB patients. Herein, we explored whether the MTB antigen-stimulated TNF-α release would be useful for monitoring responses to anti-TB treatment. We compared unstimulated (TNF-αNil), MTB antigen-stimulated (TNF-αAg), and MTB antigen-stimulated minus unstimulated TNF-α levels (TNF-αAg-Nil) in supernatants from QuantiFERON-TB Gold In-Tube tests before and after treatment in 16 active TB patients, 25 latent TB infection (LTBI) subjects, and 10 healthy controls (HC). TNF-αAg and TNF-αAg-Nil levels decreased significantly after treatment in patients with active TB. In addition, TNF-αNil, TNF-αAg, and TNF-αAg-Nil levels were significantly higher in untreated active TB patients compared to LTBI subjects and HC. This finding cautiously suggests that MTB Ag-stimulated TNF-α response may be a potential adjunctive marker for monitoring treatment response in active TB patients.

Comparison of the 2-step tuberculin skin test and QuantiFERON-TB Gold in-Tube test in the screening of latent tuberculosis infection in cancer patients

Interferon-γ release assay (IGRA) may improve the diagnostic accuracy for latent tuberculosis infection (LTBI). The aim of this study was to compare the performance of the QuantiFERON-TB Gold-in-Tube (QFT-GIT), with the tuberculin skin test (TST) (one and two step TST) in detection of LTBI in immunocompromised cancer patients.The study was carried out on 50 patients and 20 healthy subjects as a control group. Patients with active TB or AIDS were excluded. A TSTI was only positive in 2 patients (4%). The TSTII (booster phenomena) was positive in 8 patients (16%) after 3–4weeks. Ten patients (20%) had positive Quantiferon test while the test was indeterminate in 14 patients (28%).Hematological malignancy group (HMgroup) had significantly more positive TSTII results followed by the breast cancer group (p=0.01). Similarly, QFT-GIT positive values were significantly more frequent in the HM group. This study suggests that the QFT-GIT test maintains its sensitivity and performance in immunocompromised cancer patients, identifying a large number of truly infected patients being anergy to the tuberculin skin test.

Diagnostic values of the QuantiFERON-TB Gold In-tube assay carried out in China for diagnosing pulmonary tuberculosis.

BackgroundInterferon-release assays (IGRAs) for diagnosing active pulmonary tuberculosis (PTB) are not yet fully validated, particularly in high TB-endemic areas as the People's Republic of China (PRC). The aim of this report was to assess the performance of the QuantiFERON-TB Gold In-tube (QFT-GIT) and tuberculin skin test (TST), in addition to microbiological results, as contributors for diagnosing active PTB in the PRC.Methods/Principal FindingsA total of 300 PTB patients, 41 disease controls (DC) and 59 healthy community controls (HCC) were included prospectively between May 2010 and April 2011 from two provinces of the PRC (Heilongjiang and Zhejiang). The QFT-GIT and TST yielded an overall sensitivity for active TB of 80.9% and 86.2%, and a specificity of 36.6% and 26.8%, respectively. The province of origin and smear microscopy status did not significantly impact the diagnostic values for PTB. However, using the TST with a 10 mm cut-off point, a significantly higher proportion of LTBI was observed in the DC than the HCC (p=0.01). Discordant results between the QFT-GIT and TST were found among 1/3 of the PTB, HCC and DC. Two-thirds of the individuals presented TST-positive/QFT-GIT-negative discordant results. The TST-negative/QFT-GIT-positive result was not associated with age or bacillary load. Cumulative QFT-GIT and TST positive results increased the overall sensitivity (95.9%), but it was associated with a dramatic decrease of the overall specificity (24.8%) leading to a suboptimal PPV (80.1%) and a low NPV (61.1%).Conclusions/SignificanceThe usefulness of the QFT-GIT to diagnose active TB in high TB-endemic countries remains doubtful because like the TST, the QFT-GIT cannot distinguish between LTBI and active TB. Used as single stand-alone tests, both the QFT-GIT and TST have very limited roles in the diagnosis of active PTB. However, the combined use of SM, the TST and QFT-GIT may allow for the exclusion of ATB.

Sa1266 Interferon-γ Release Assay Versus Tuberculin Skin Test in Patients With Moderate-to-Severely Active Ulcerative Colitis: Results From the PURSUIT UC Program

Objective: To report results of an interferonΥ release assay (IGRA) vs standard tuberculin skin test (TST) as a screening tool for latent TB infection in patients with UC in PURSUIT. Methods: Patients with moderately to severely active UC were screened for latent TB using the standard TST and the IGRA to assess eligibility for entry into the induction studies of golimumab (PURSUIT-SC [C0524T17]and PURSUIT-IV [C0524T1]Any patient with a newly identified positive finding for TB on a diagnostic test in whom there was no evidence of active TB was permitted to enter provided appropriate treatment for latent TB was initiated before or at the time of the first dose of study agent. TST was performed according to the Mantoux method, using 5 tuberculin units (TU) of purified protein derivative (PPD) standard or 2 TU of PPD RT-23. The TST was deemed positive for latent TB infection according to the local country guidelines for defining an immunosuppressed host or, in the absence of local guidelines, according to the presence of induration >5mm. The IGRA used to screen for latent TB was the QuantiFERON-TB Gold In-Tube test. Overall IGRA and TST results were assessed. The impact of prior BCG vaccination and concomitant medication (ie corticosteroids and/or immunomodulators ) on outcome was assessed. Results: 1283 patients had both IGRA and TST screening prior to GLM treatment. Among these patients, 8.7% had at least one test yielding positive findings for latent TB, including 6.2% with positive results

Risk Assessment of Tuberculosis in Contacts by IFN-γ Release Assays. A Tuberculosis Network European Trials Group Study.

Latent infection with Mycobacterium tuberculosis is defined by a positive IFN-γ release assay (IGRA) result in the absence of active tuberculosis. Only few, mostly monocentric studies have evaluated the role of IGRAs to predict the development of tuberculosis in recent contacts in low-incidence countries of tuberculosis. To analyze IGRA results and the effect of preventive chemotherapy on tuberculosis progression rates among recent contacts. Results from contact investigations at 26 centers in 10 European countries including testing for latent infection with M. tuberculosis by the QuantiFERON-TB Gold In-Tube (QFT) test or the T-SPOT.TB (TSPOT) were prospectively collected and analyzed. Among 5,020 contacts of 1,023 index cases, 25 prevalent secondary cases were identified at screening. Twenty-four incident cases occurred among 4,513 contacts during 12,326 years of cumulative follow-up. In those with a positive IGRA result, tuberculosis incidence was 0.2 (QFT) and 0 (TSPOT) per 100 patient-years when contacts received preventive chemotherapy versus 1.2 (QFT) and 0.8 (TSPOT) per 100 patient-years in those not treated (38 and 37 patients needed to be treated to prevent one case, respectively). Positive and negative predictive values were 1.9% (95% confidence interval [CI], 1.1-3.0) and 99.9% (95% CI, 99.7-100) for the QFT and 0.7% (95% CI, 0.1-2.6) and 99.7% (95% CI, 99.1-99.9) for the TSPOT. Tuberculosis rarely developed among contacts, and preventive chemotherapy effectively reduced the tuberculosis risk among IGRA-positive contacts. Although the negative predictive value of IGRAs is high, the risk for the development of tuberculosis is poorly predicted by these assays.

The dynamics of QuantiFERON-TB gold in-tube conversion and reversion in a cohort of South African adolescents.

Interferon-γ release assays are used to diagnose tuberculosis infection. In developed countries, high rates of reversion following conversion have been described. To assess QuantiFERON TB Gold In-Tube test (QFT) conversion and reversion dynamics in a tuberculosis-endemic setting. Adolescents aged 12-18 years residing near Cape Town were recruited. Tuberculin skin tests (TSTs) and QFTs were performed at baseline and after 2 years of follow up. Half of the participants had TST and QFT performed at additional time points. Participants were observed for incident tuberculosis disease for up to 5 years. Among 5,357 participants, 2,751 (51.4%) and 2,987 (55.8%) had positive QFT and TST results, respectively, at baseline. Annualized QFT and TST conversion risks were 14.0 and 13.0%, respectively, and reversion risks were 5.1 and 4.1%, respectively. Concordance was excellent for conversions (κ = 0.74), but poor for reversions (κ = 0.12). Among recent QFT converters, the magnitude of the QFT value was strongly inversely associated with risk of reversion (P < 0.0001). When longitudinal QFT data were analyzed in a cross-sectional manner, the annual risk of infection was 7.3%, whereas inclusion of reversions in the analysis showed that the actual risk of infection was 14.0%. Incident tuberculosis was 8-fold higher among QFT reverters than in participants with all negative QFT results (1.47 vs. 0.18 cases/100 person-years, P = 0.011). In this tuberculosis-endemic setting, annual risk of infection was extremely high, whereas QFT and TST conversion concordance was higher and QFT reversion rates were lower than reported in low-burden settings.

EFFICACY OF INTERFERON-INDUCIBLE PROTEIN-10 FOR MONITORING STANDARD TUBERCULOSIS TREATMENT

Introduction: Tuberculosis (TB) remains a major global health problem. Interferon-inducible Protein-10 (IP-10) has been proposed as a promising biomarker for monitoring the efficacy of standard therapy in patients with active pulmonary TB. Objective: The propose of this study was to assess the efficacy of IP-10 in patients with active pulmonary TB as a sign of a response to TB standard therapy. Patients and methods: A total of 136 newly diagnosed pulmonary tuberculosis patients were recruited in this study. The patients were classified into 2 groups according to the presence of the risk factors of relapse. Group (1) included 30 patients with low risk of relapse and group (2) included 25 patients with moderate and high risk of relapse. In this study, we assessed the IP-10 levels in both serum and in response to QuantiFeron-TB Gold In-Tube test (QFT-GIT) antigens at time of diagnosis, at month 2 and after completing treatment. Results: IP-10 median levels in both serum and in response to QFT-GIT antigens were not significantly different between both patient groups at baseline, at month 2 and after completion of TB treatment. However, in each patient group, medians of IP-10 levels before treatment decreased significantly with time at 2 months and after the completion of anti-TB treatment (all P < 0.05). Conclusion: Interferon-inducible Protein-10 (IP-10) in serum or in response to QFT-GIT antigens was a useful biomarker for monitoring the efficacy of the standard regimen in patients with active pulmonary TB. Keywards: Interferon-inducible Protein-10, Monitoring, Tuberculosis. Abbreviations: Interferon-inducible Protein-10 (IP-10), QuantiFeron-TB Gold In-Tube test (QFT-GIT), Tuberculosis (TB), Acid-fast bacilli (AFB), Tuberculin test (TST), Chest X-ray (CXR).

Development and evaluation of a new interferon-gamma release assay for the diagnosis of tuberculosis infection in HIV-infected individuals in China

Background: Human immunodeficiency virus (HIV)-infected individuals are at high risk of contracting tuberculosis (TB) disease, and current methods for diagnosing TB infection are less effective in this population. We developed and evaluated a new interferon-gamma release assay (IGRA), named A.TB, in HIV-infected individuals, with and without active TB, in a setting of high TB burden and low HIV prevalence. Methods: A total of 255 subjects were divided into 3 groups according to their HIV and TB status: HIV+ without active TB (n = 123), HIV+/TB+ (n = 79), and HIV–/TB+ (n = 65). The A.TB assay was performed in parallel with the QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST). Results: The positive rate was 59.3% (n = 123) by A.TB and 53.8% (n = 106) by QFT-GIT. We observed a strong concordance of 81.2% (k = 0.612) between the two IGRAs. The QFT-GIT results were affected by low CD4+ cell count (p = 0.013), while A.TB results were not. A.TB was also performed in patients with active TB (n = 65) and patients with active TB and HIV co-infection (n = 79). The sensitivity of A.TB in these groups was 80.0% and 81.0%, respectively. Conclusion: The A.TB results were not affected by low CD4+ cell count in the co-infected cohort. With further evaluation, A.TB may prove to be a valuable tool for diagnosing TB in HIV-infected patients.

Serial QuantiFERON-TB Gold In-Tube testing for psoriatic patients receiving antitumor necrosis factor-alpha therapy

Tumor necrosis factor-α (TNF-α) antagonists have become increasingly popular in the treatment of psoriasis. However, the increased risk of latent tuberculosis infection (LTBI) reactivation has also become an important issue in clinical practice. The aim of this study was to evaluate serial QuantiFERON-TB Gold In-Tube (QFT-GIT) testing for detecting LTBI among a cohort of psoriatic patients vaccinated with bacille Calmette-Guérin in a country with an intermediate burden of TB during long-term treatment with TNF-α antagonists. We enrolled psoriatic patients treated with TNF-α antagonists who also accepted yearly serial QFT-GIT testing and regular chest X-ray examinations before and during the anti-TNF-α treatment from January 2010 to August 2014. Patients diagnosed with LTBI received chemoprophylaxis, and QFT-GIT testing was performed in these patients after completion of chemoprophylaxis. In this retrospective study, 101 patients had completed baseline and at least 1 year of follow-up. Among these patients, 60 had continued TNF-α antagonists therapy and received examinations in the 2 nd year, whereas 18 had continued the therapy until the 3 rd year. The conversion rate among these patients was 14.29% (13/91). In this study, 23 patients were diagnosed with LTBI according to the positive results obtained in the QFT-GIT test, with 19 of them having completed chemoprophylactic therapy. Follow-up QFT-GIT testing revealed reversion in 11 patients (57.89%) and decreased interferon-γ (IFN-γ) levels (68.42%) in 13 patients. Patients over 45 years of age tended to have a persistent positive result. This study demonstrated that 14.29% of psoriatic patients undergoing long-term TNF-α antagonist therapy had a QFT-GIT conversion. Although a decreased IFN-γ level and QFT-GIT reversion were observed in most cases following prophylactic therapy, the value of QFT-GIT for evaluating the effect of LTBI prophylaxis remains controversial.

Contribution of the QuantiFERON-TB Gold-in Tube test in the diagnosis of latent tuberculosis in children living with smear-positive pulmonary tuberculosis patients

Aims and objectivesPeople living in contact with smear-positive pulmonary tuberculosis (PTB) patients are highly exposed to TB infection, including children who are a major risk group.TB disease, among those who become infected, manifests itself mainly in the two years (90%) after the identification of the index case. The latent TB infection can be detected by means of two tests: the tuberculin skin test (TST) and the IGRAs test – QuantiFERON-TB Gold in Tube (QFT-G). The latter showed greater specificity in the prediction of latent TB infection in an adult population, but not in a child population.The main objective of this study is to estimate the incidence of TB disease in children living in contact with an M+ Pulmonary tuberculosis index case (PTM+) according to the positivity of the Quantiferon test and/or the tuberculin skin test (TST), during the two years following exposure. The results of this study will eventually rehabilitate the national guidelines on individual contacts. MethodsIt is a descriptive study, cohort-type, prospective, multicenter, conducted amongst children in contact with a PTM+ case, aged between 6months and 15years, and followed for two years in order to estimate the incidence of TB disease in different groups defined by the results of the Quantiferon test and the TST.The recruitment of children will be based on the PTM+ index case diagnosed and taken in charge by the Services of Control of Tuberculosis and Respiratory Diseases (SCTMR) located in the Wilaya of Algiers, diagnosed in 2014. Seven centers were selected. ResultsThis initial work will describe the clinical characteristics of the index case diagnosed during 2014 (December 2013–October 2014) and the results of the TST and Quantiferon test carried out in children contacts at the time of their recruitment. At the time, 396 children living in contact with M+PT have been tested with Tuberculin and QFT-G. They are maintained under control during at least two years.

Comparison of interferon gamma release assay & tuberculin skin tests for diagnosis of latent tuberculosis in patients on maintenance haemodialysis.

Background & objectives:Tuberculosis (TB) is a common infection in patients on haemodialysis. There is a definite role of treatment of latent TB (LTB) in these patients. However, diagnosis of LTB in these patients by tuberculin skin test (TST) is unreliable. There is suggestion that interferon gamma release assay (IGRA) will be more reliable test for diagnosis of LTB in this setting. Thus, we evaluated value of IGRA and TST for the diagnosis of LTB in patients on dialysis in an Indian setting.Methods:Patients with end stage kidney disease on dialysis were included. Patients with active TB were excluded. Each patient was subjected to TST (induration of ≥10 mm was taken as positive) and QuantiFERON TB Gold In-Tube test (QFT-GIT) for diagnosis of LTB.Results:A total of 185 patients were included; 129 (69.7%) were males and mean age was 36.7 ± 12.3 yr. Past history of TB was present in 18 (9.7%) patients. One hundred and thirty four (72.4%) patients had scar of BCG vaccination. QFT-GIT test was positive in 66 (36%), TST in 32 (17%) and both in 13 (7%) patients. Of the 66 patients positive with QFT-GIT, only 13 (19.6%) were positive for TST. Of the 32 patients positive with TST, only 13 (40.6%) were positive with QFT-GIT; 100 (54%) patients were negative for both the tests. Overall, 85 (45.9%) patients were positive for either of the two tests. Poor agreement was shown between the two methods. On logistic regression analysis, odds of QFT-GIT to be positive in patients with BCG vaccination was 1.23 and with history of TB 0.99, both being insignificant. odds of tuberculin skin test to be positive in patients with BCG vaccination was 1.04 and with history of TB 0.99, both again being insignificant.Interpretation & conclusions:Our findings showed that more number of patients (36%) on haemodialysis were positive for QuantiFERON Gold In-Tube test as compared to TST (17%). There was poor agreement between the two tests. No significant effect of BCG vaccination and history of TB in past was observed on both tests.

Performance of an interferon-gamma release assay in the diagnosis of tuberculous meningitis in children / Performanţa testului bazat pe eliberarea interferonului gamma în diagnosticul meningitei tuberculoase la copil

AbstractThe new immunodiagnostic tests based on the Mycobacterium tuberculosis specific antigen, early secretory antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10), showed promising results in the diagnosis of tuberculosis infection. However, there are only few studies in the published literature on performance tests in cerebrospinal fluid. We investigated whether a rapid diagnosis of tuberculous meningitis (TBM) could be established by interferon-γ blood and cerebrospinal fluid (CSF) tests in children.We used the QuantiFERON-TB Gold in Tube test (QFT-IT) on blood and the QuantiFERON-TB Gold test (QFT-G) on the CSF of 63 subjects with TBM (including 25 case of definite TBM and 38 cases of probable TBM) and 62 controls.The CSF analyses indicated possible TBM in 63.4% of cases. The sensitivity of the CSF culture for Mycobacterium tuberculosis was only 39.6%. The sensitivity of the tuberculin skin test (TST) was 49.2% and the specificity was 88.6%. The estimated sensitivities of the QFT-G for the CSF and QFT-IT for the blood in culture confirmed TBM cases (gold standard) were 84% and 80%, respectively. The estimated specificities were 98.2% for the CSF and 87.9% for the blood. This study showed that the sensitivity of QFT for the CSF could be higher than TST and culture and slightly higher in CSF than in blood. The specificity of QFT-G for the CSF was higher those of the TST, but the specificity of QFT-IT is lower.QFT-G of the CSF is a useful diagnostic marker of tuberculosis that may improve the management of TBM, but the test results must be correlated with clinical, radiological and characteristics of CSF. New researches are needed to investigate the performance of QFT-G in the CSF compared with ELISPOT and PCR

The use of Quantiferon-TB gold in-tube test in screening latent tuberculosis among Saudi Arabia dialysis patients.

BACKGROUND AND AIM:Screening for tuberculosis (TB) is a key strategy for controlling infection. This study aimed to detect latent TB among dialysis patients.METHODS:This is a prospective study conducted in King Saud University, Riyadh involving hemodialysis (HD) and peritoneal dialysis (PD) patients aged ≥18 years. Patients were screened for latent TB infection (LTBI) using both TBskin test (TST) and QuantiFERONTB Gold In-Tube test (QFT-GIT). All participants were followed-up clinically and radiologically every 3 months for 2 years.RESULTS:A total of 243 (181 HD and 62 PD) patients were included and 112(46.1%) were males. 45.3% showed positive QFT in HD patients with sensitivity of 91.7%, specificity of 71.4%, positive predictive value (PPV) of 19.5%, and negative predictive value (NPV) of 91.1%. TST results in HD showed that positive TST was 17.4%, sensitivity was 63.2%, specificity was 95.5%, PPV was 51.5%, and NPV was 91.1%. Five (8.1%) showed positive QFT in PD patients with sensitivity of 7.7%, specificity of 91.8%, PPV of 6.6%, and NPV of 92.3%. TST results in PD showed that positive TST was 9.8%, sensitivity was 35.7%, specificity was 97.9%, PPV was 55.8%, and NPV was 93.3%. Previous TB infection was significantly correlated with QFT only in HD patients, but significantly associated with TST in both HD and PD patients. Also in HD, QFT was significantly associated with TST (P = 0.043).CONCLUSIONS:Due to high variability of QFT-GIT sensitivity, we recommend its use for its NPV and to use either TST or QFT in screening latent TB.