Use Of QuantiFERON-TB Gold In-Tube Research Articles

QuantiFERON®-TB Gold In-Tube reliability for immigrants with parasitic infections in Boston, USA.

<sec id="st1"> <title>SETTING</title> Accurate testing and treatment for latent tuberculous infection is necessary for tuberculosis elimination. Certain parasite infections are associated with increased tuberculin skin test positivity; species-specific effects on QuantiFERON®-TB Gold In-Tube (QGIT) have not been described. </sec> <sec id="st2"> <title>OBJECTIVE</title> To determine whether infection with helminths or protozoa affects QGIT results. </sec> <sec id="st3"> <title>DESIGN</title> We retrospectively analyzed QGIT and parasite testing results for immigrants screened in Boston, MA, USA, from 2012 to 2017. We also prospectively measured cytokines in QGIT supernatants for a subset (n = 68) with 1) helminths, 2) Blastocystis hominis, 3) other protozoa, and 4) no parasites. </sec> <sec id="st4"> <title>RESULTS</title> Of 527 immigrants screened, 141 (26.8%) were QGIT-positive and 229 (43.4%) had parasites detected: 27/527 (5.1%) had helminths and 202/527 (38.3%) protozoa. Cytokine analysis revealed increased interleukin-10 concentrations with protozoa (P = 0.04), and non-significantly higher T-helper 2 concentrations with helminths compared with no parasites. No significant differences emerged in QGIT positivity or interferon-gamma concentrations in any group. </sec> <sec id="st5"> <title>CONCLUSION</title> Study results support the use of QGIT in parasite-endemic settings. </sec>.

QuantiFERON-TB Gold In-Tube in Saudi Arabia benchmarked with other sites of the Middle East: A meta-analysis review.

Screening for Latent Tuberculosis Infections (LTBI) constitutes a key step in health surveillance programs especially among adults of high-risk groups. To our knowledge, this is the first systematic and meta-analysis review that aims to critically assess and compare the agreement of QuantiFERON-TB Gold In-Tube (QFT-GIT) and Tuberculin Skin Testing (TST) among adults of high-risk groups in Saudi Arabia and compare results with other sites of the Middle East. Kappa estimates were meta-analyzed using random effect model and several subgroup analyzes were performed to explain overall heterogeneity. Funnel plot, Begg's and Egger's tests were employed to assess overall publication bias. 18 studies were meta-analyzed, comprising 5070 adults of high-risk groups. Pooled kappa estimates from Saudi Arabia (κ = 0.29, 95% CI: 0.16, 0.41) showed lower rate of agreement compared to other sites of the Middle East (κ = 0.33, 95% CI: 0.25, 0.41). However, a significant level of heterogeneity (I2 = 96.7%, p > 0.001) were identified across collected evidence. Begg's and Egger's tests confirmed absence of significant publication bias in this review (p = 0.49 and p = 0.16, respectively). This work revealed fair to poor agreement between TST and QFT-GIT, indicating that these two tests are not interchangeable in such settings. Substantial evidence is still needed before considering the sole use of QFT-GIT as an alternative to TST in these populations. Moreover, there is an urgent need for longitudinal studies in Saudi Arabia and the Middle East to accurately assess precision of LTBI diagnosis.

Quantiferon-TB Gold In-Tube Improves Tuberculosis Diagnosis in Children

The diagnostic accuracy of Quantiferon-TB Gold In-Tube (QFT-IT) is uncertain in the pediatric population, while tuberculin skin test (TST) is still conventionally used despite its limitations. The aim of this study was to compare the performance of QFT-IT with TST in a large cohort of children screened for tuberculosis (TB) infection because of contact tracing, suspected TB, arrival from endemic country or immunosuppressive therapy. A retrospective analysis was conducted on 517 children 0-14 years of age evaluated at the pediatric unit of the S. Orsola-Malpighi University Hospital of Bologna, Italy; 366 of them were also tested with TST. Results were analyzed for Calmette-Guérin bacillus vaccination, country of origin, reason for testing, diagnosis and age. The overall agreement between the 2 tests was 89.9%, but it was highly affected by Calmette-Guérin bacillus vaccination (P < .0001). According to diagnosis and age, QFT-IT detected latent tuberculous infection cases better than TST in all age groups. Sensitivity for diagnosing active TB in symptomatic children was higher for QFT-IT than TST (93.3% vs. 86.5%), especially in children younger than 2 years, while specificity was high for both tests (99.3% and 98.8%, respectively). Low rate of indeterminate QFT-IT results (3.9%) was not differently distributed among age groups, but was associated with diagnosis of TB exclusion (P < 0.0001), mainly pneumonia (35%), and to Italian children (P = 0.0024). Despite the concern about the use of QFT-IT in children because of their immature immune system, our results suggest the preferential use of QFT-IT as a support tool for diagnosis and management of TB, even in infants.

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.

IFN-γ Release Assays in the Diagnosis of Latent Tuberculosis Infection among Immunocompromised Adults

Immunocompromised persons with latent tuberculosis infection (LTBI) are at increased risk for tuberculosis reactivation compared with the general population. The tuberculin skin test, the traditional assay for diagnosing LTBI, has reduced accuracy in immunocompromised patients. IFN-γ release assays (IGRAs) are in vitro blood tests that measure T-cell release of IFN-γ after stimulation with antigens unique to Mycobacterium tuberculosis. Here we review the data for the use of QuantiFERON-TB Gold In-Tube and T-SPOT.TB, the two currently available IGRAs, in immunocompromised adults, including persons infected with HIV, patients with immune-mediated inflammatory disorders, candidates for treatment with tumor necrosis factor-α inhibitors, patients receiving hemodialysis, solid-organ transplant recipients, and patients with cancer. On the basis of the available data, IGRAs have advantages over the tuberculin skin test in specific patient populations and in certain situations. Further studies are needed to more accurately define the usefulness of IGRAs in immunocompromised patients.

TB Screening in Canadian Health Care Workers Using Interferon-Gamma Release Assays

BackgroundWhile many North American healthcare institutions are switching from Tuberculin Skin Test (TST) to Interferon-gamma release assays (IGRAs), there is relatively limited data on association between occupational tuberculosis (TB) risk factors and test positivity and/or patterns of test discordance.MethodsWe recruited a cohort of Canadian health care workers (HCWs) in Montreal, and performed both TST and QuantiFERON-TB Gold In Tube (QFT) tests, and assessed risk factors and occupational exposure.ResultsIn a cross-sectional analysis of baseline results, the prevalence of TST positivity using the 10 mm cut-off was 5.7% (22/388, 95%CI: 3.6–8.5%), while QFT positivity was 6.2% (24/388, 95%CI: 4–9.1%). Overall agreement between the tests was poor (kappa = 0.26), and 8.3% of HCWs had discordant test results, most frequently TST−/QFT+ (17/388, 4.4%). TST positivity was associated with total years worked in health care, non-occupational exposure to TB and BCG vaccination received after infancy or on multiple occasions. QFT positivity was associated with having worked as a HCW in a foreign country.ConclusionsOur results suggest that LTBI prevalence as measured by either the TST or the QFT is low in this HCW population. Of concern is the high frequency of unexplainable test discordance, namely: TST−/QFT+ subjects, and the lack of any association between QFT positivity and clear-cut recent TB exposure. If these discordant results are indeed false positives, the use of QFT in lieu of TST in low TB incidence settings could result in overtreatment of uninfected individuals.

Estudio de contactos en niños y adolescentes usando el QuantiFERON-TB ® gold in-tube

Objective To compare the results of the Mantoux Tuberculin Test (TT) and the QuantiFERON TB ® Gold In-Tube (QFT-GIT) in a population of children and adolescents with TB contacts. Material and methods A prospective study using data collected on children and adolescents (< 17 years) from a Health District of 300,000 inhabitants in the Basque Country (Spain) recruited into a TB contact study over a period of almost three years. The study included performing the Tuberculin Test using the Mantoux technique (with 2-TU of RT-23 PPD RT23 and Tween 80), and the QFT-GIT simultaneously, and collecting the demographic and clinical data. Results Of the 160 children included in the study, 14% had a positive TT (≥ 5 mm) and 11% a positive QFT-GIT. There was 95%-96% agreement between the tests, depending on the TT cut-off point chosen, and was higher in non-vaccinated children (100%) and in children less than 5 years-old (100%). A significant relationship was observed between a positive result for both tests with exposure in the home. The use of QFT-GIT in the screening of latent TB infection could reduce preventive treatments by 28%-34% compared with conventional screening with the TT. Conclusions The behaviour of QFT-GIT was comparable to the TT in identifying children with a tuberculosis infection; therefore it could potentially replace the TT.

Interferon-γ Release Assay among Tuberculin Skin Test Positive Students in Korean High Schools

Background: There are several active tuberculosis (TB) cases in Korean high schools each school year. The risk of transmission in schools is extremely high due to the considerable time spent in closed classrooms. We evaluated the control of latent tuberculosis infection in Korean high schools. Methods: When a student was identified with active TB, tuberculin skin testing was performed on their classmates and on students in their same school grade. When a student had a positive tuberculin skin tests (TST), they underwent follow-up testing with QuantiFERON-TB Gold In-Tube (QFT). The manufacturer recommended a cut-off of 0.35 IU/mL to determine QFT positivity was applied. Results: A total of 131 pulmonary tuberculosis (TB) patients were included based on the criteria for screening TB contacts in the National Tuberculosis Control Program. Seventy-five (57.2%) students tested smear positive. TST were performed on 7,109 students who were classmates of, or in the same grade as, a TB patient. Of the contacts, 1,231 students (17.3%) were TST positive and they were screened with QFT. Six hundred-sixty-six (55.0%) of the tested students returned a positive QFT result and the rate of positivity was significantly associated with the increasing size of TST indurations (p ＜0.0001). Conclusion: The use of QFT resulted in approximately 45% of TST positive students not being given chemoprophylaxis.

Diagnosis of Tuberculous Uveitis: Clinical Application of an Interferon-gamma Release Assay

To determine the role of the QuantiFERON-TB Gold In-Tube (QFT) (Cellestis Inc., Carnegie, Australia) assay in the diagnosis of tuberculosis (TB) uveitis. Retrospective cohort study. The study included 157 patients with suspected TB uveitis seen over an 18-month period (August 1, 2006, to February 31, 2007) at the Singapore National Eye Center (SNEC) uveitis clinic. We identified all cases of suspected TB uveitis in the above-mentioned time period and reviewed all medical records of the cases. Clinical findings, type of treatment instituted, response to treatment, and results of investigations such as QFT, tuberculin skin test (TST), and chest x-rays were recorded. A novel method of using treatment response to determine the presumed diagnosis of TB was used to estimate the accuracy of QFT and TST. The positive likelihood ratio (LR+), negative likelihood ratio (LR-), and area under the receiver operator characteristic curve (ROC) of the investigations were estimated. QFT is not superior to the TST in sensitivity as a screening test or first-line study in TB-related uveitis; however, QFT is more specific than the TST in identifying infections by Mycobacterium tuberculosis. Negative QFT tests should be interpreted with caution, because they do not exclude the diagnosis. The new QFT is only slightly superior to the TST in the diagnosis of TB uveitis. Thus, there is an important role for interpreting the QFT together with the TST. This is the first and largest study of its kind to evaluate the use of QFT in the clinical diagnosis of TB uveitis.

P2006 The use of QuantiFERON-TB Gold In-Tube to screen for tuberculosis infection in employees of a Swiss university hospital

P2006 The use of QuantiFERON-TB Gold In-Tube to screen for tuberculosis infection in employees of a Swiss university hospital