scholarly journals Association of Low Sputum Smear Positivity among Tuberculosis Patients with Interferon-Gamma Release Assay Outcomes of Close Contacts in Japan

Author(s):  
Tsuyoshi Ogata ◽  
Natsuki Nagasu ◽  
Ritei Uehara ◽  
Kunihiko Ito

Risk prediction and response measures may differ in tuberculosis (TB) patients with low sputum smear positivity for acid-fast bacillus (AFB) compared to those who are smear negative. However, previous studies using the tuberculin skin test (TST) did not show that differences in measures are important. This study compared results of interferon-gamma release assays (IGRA) between contacts of pulmonary TB patients with AFB smear positivity and those with smear negativity using QuantiFERON®-TB Gold In-Tube (QFT) assays. Close contacts of TB patients with culture-confirmed infections between April 2010 and December 2012 in Ibaraki, Japan, were enrolled, and 439 Japanese contacts of 129 index TB patients were examined. Adjusted odds ratios of QFT in contacts were 0.68 (95% confidence interval: 0.17–2.8) for AFB scanty patients, 1.12 (0.45–2.8) for AFB 1+, 1.20 (0.48–3.0) for AFB 2+, and 4.96 (1.9–12.9) for AFB 3+, compared to those who were smear negative. Differences in IGRA positivity were not significant between close contacts of TB patients with low positive and negative smears.

2021 ◽  
Vol 6 (1) ◽  
pp. e000663
Author(s):  
Samra Rahman ◽  
Muhammad Irfan ◽  
M A Rehman Siddiqui

Tuberculosis (TB)-associated uveitis is a common cause of infectious uveitis in the developing world. Diagnosis of TB uveitis remains a challenge. The role of interferon gamma release assays (IGRAs) is uncertain. Herein we summarise the available literature on the utility of IGRAs in the diagnosis and management of TB uveitis. We searched PubMed database from 1 August 2010 to 31 July 2020 using the following keywords alone and in combination: ‘interferon-gamma release assay’, ‘QuantiFERON’, ‘T-SPOT.TB’, ‘TB uveitis’, ‘serpiginous like choroiditis’, ‘tuberculoma’, ‘TB vasculitis’, ‘TB panuveitis’ and ‘ocular tuberculosis’. Data from 58 relevant studies were collated. The review is focused on currently marketed versions of IGRA tests: QuantiFERON-TB Gold In-Tube assay, QuantiFERON-TB Gold Plus assay (QFT-Plus) and T-SPOT.TB. We found limited evidence regarding the diagnostic utility of IGRA in patients with uveitis. No study was identified evaluating the newer QFT test—the QFT-Plus—in patients with uveitis. Similarly, there is lack of data directly comparing QFT-Plus with T-SPOT.TB specifically for the diagnosis of TB uveitis.


2009 ◽  
Vol 16 (8) ◽  
pp. 1170-1175 ◽  
Author(s):  
A. K. Detjen ◽  
L. Loebenberg ◽  
H. M. S. Grewal ◽  
K. Stanley ◽  
A. Gutschmidt ◽  
...  

ABSTRACT Interferon gamma release assays (IGRAs) have been shown to be sensitive and highly specific for the detection of immune memory against Mycobacterium tuberculosis. Little is known about the reproducibility and within-person variability of these assays. Various aspects of short-term reproducibility of a commercial IGRA, the QuantiFERON-TB Gold In-Tube (QFT-IT) assay, were assessed. The QFT-IT assay was performed twice within 3 days in 27 health care workers in Cape Town, South Africa. Two sets of tests were performed by different operators on day 1, and one set was performed on day 3. Aspects such as interoperator, intraoperator, day-to-day variability, and test-retest variability as well as different the storage methods of plasma were investigated. Seventeen of 27 (63%) of participants had at least one positive QFT-IT text; six had discordant results. The agreement of all aspects studied was high, with kappa values between 0.82 and 1.00 for dichotomous measures, and interclass correlations (ICC) of 0.809 to 0.965 were observed for continuous gamma interferon (IFN-γ) measures. The variability of the magnitude of response was highest comparing measures obtained from individuals on different days (ICC of 0.809). The magnitude of the IFN-γ responses between assays performed for individual participants was variable, with ranges from 0.03 to 11 IU/ml, resulting is discordant results for five participants. The results indicate that the QFT-IT assay is a robust and highly reproducible assay. Considerable intraindividual variability occurs in the magnitude of IFN-γ responses, which may influence the interpretation of serial measures.


2021 ◽  
Author(s):  
Allyson Guimaraes Costa ◽  
Brenda K.S. Carvalho ◽  
Mariana Araujo-Pereira ◽  
Hiochelson N.S. Ibiapina ◽  
Renata Spener-Gomes ◽  
...  

Background: Interferon-gamma release assay (IGRA) has emerged as a useful tool in identifying latent tuberculosis infection (LTBI). This assay can be performed through testing platforms, such as QuantiFERON-TB Gold Plus (QFT-Plus). This in vitro test has been incorporated by several guidelines worldwide and has recently been considered for the diagnosis of LTBI by the World Health Organization (WHO). The possibility of systematically implementing IGRAs such as QFT-Plus in centers that perform LTBI screening has been accelerated by the decreased availability of tuberculin skin testing (TST) in several countries. Nevertheless, the process to implement IGRA testing in routine clinical care has many gaps. Methods: The study utilized the expertise acquired by the laboratory teams of the Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil consortium during study protocol implementation of LTBI screening of TB close contacts. Results: RePORT-Brazil includes clinical research sites from Brazilian cities and is the largest multicenter cohort of TB close contacts to date in the country. Operational and logistical challenges faced during IGRA implementation in all four study laboratories are described, as well as the solutions that were developed and led to the successful establishment of IGRA testing in RePORT-Brazil. Conclusions: The problems identified and resolved in this study can assist laboratories implementing IGRAs, in addition to manufacturers of IGRAs providing effective technical support. This will facilitate the implementation of IGRA testing in countries with a high TB burden, such as Brazil.


2018 ◽  
Vol 56 (12) ◽  
Author(s):  
S. A. R. Siegel ◽  
M. Cavanaugh ◽  
J. H. Ku ◽  
L. M. Kawamura ◽  
K. L. Winthrop

ABSTRACT Interferon gamma release assays (IGRAs) are important tools in identifying prior tuberculosis exposure. The new-generation QuantiFERON-TB Gold Plus (QFT-Plus) assay, recently approved for use in the United States, differs from the current-generation QFT Gold-In-Tube (QFT-GIT) assay with the addition of a second antigen tube that also contains novel CD8+ T-cell-stimulating peptides. The QFT-Plus assay has increased sensitivity in immunocompromised populations, and we sought to assess the specificity of QFT-Plus compared to that of QFT-GIT in low-risk individuals. We enrolled adults without tuberculosis risk factors, including a subgroup with pulmonary nontuberculous mycobacterial (NTM) disease due to Mycobacterium avium complex (MAC) or Mycobacterium abscessus. The primary outcome measures included specificity, interassay concordance, and agreement between the QFT-Plus and QFT-GIT assays. Of 262 participants enrolled, 51 had pulmonary NTM. The median age was 39 years (age range, 18 to 78 years); 73% were female. Among the 262 individuals who were enrolled, 5 (1.9%) individuals had positive QFT-Plus results, and 3 of these individuals also had positive QFT-GIT results. The two individuals with discordant results (QFT-Plus positive/QFT-GIT negative) had only one tube positive in the QFT-Plus assay. The overall specificity of QFT-Plus and QFT-GIT was 98.1% (95% confidence interval [CI], 95.6, 99.4%) and 98.9% (95% CI, 96.7, 99.8%), respectively. The QFT-Plus specificity was similar in both the NTM (98.0% [95% CI, 89.4, 99.9%]) and non-NTM (98.1% [95% CI, 95.2, 99.5%]) groups. QFT-Plus has a high specificity, similar to that of the QFT-GIT assay, including in patients with pulmonary MAC or M. abscessus disease.


2021 ◽  
Vol 71 (11) ◽  
pp. 2543-2547
Author(s):  
Ning Xu ◽  
Wenlian Tu ◽  
Taicheng Jin ◽  
Rui Zheng ◽  
Xiaoqin Mao ◽  
...  

Objective: To assess sensitivity and specificity of the interferon gamma release assay test, and to pinpoint the influencing factors that should be taken care of in clinical application. Methods: The study was conducted at the First People's Hospital in the Yunnan Province of China from October 2018 to March 2019, and comprised samples collected from outpatient and inpatients. To detect mycobacterium tuberculosis, acid-fast staining on sputum smear was performed on relevant tissues suspected of extrapulmonary tuberculosis. Tuberculosis interferon gamma release assay test and pathology samples were examined. Tuberculosis-specific cell reaction assay kit was used for sampling. SysmexXN-2000 haematology analyser, VACUETTE SRS100/II and Beckman Coulter AU5800 were used to perform various analyses. Data was grouped and analysed using R statistical software. Results: Of the 960 samples, 516(53.75%) cases tested positive for tuberculosis infection and 444(46.25%) tested negative. The sensitivity of the pathological results was 86% and the specificity was 96%. The sensitivity of the interferon gamma release assay test was 95% and specificity 82%. Interferon release test, pathological results and final diagnosis showed significant comparisons (p<0.05). Significant relationships were also established for factors, such as age, interferon release quantity, lymphocyte, C-reactive protein and counts of mono-nuclear cell (p<0.05). Conclusions: Interferon gamma release assay test was found to have high consistency with pathological results and final diagnosis and can be used as a subsidiary to traditional clinical imaging and pathological judgment. Key Words: Tuberculosis, Interferon release, CRP, Hormone use. Continuous...  


2007 ◽  
Vol 136 (9) ◽  
pp. 1179-1187 ◽  
Author(s):  
K. OKADA ◽  
T. E. MAO ◽  
T. MORI ◽  
T. MIURA ◽  
T. SUGIYAMA ◽  
...  

SUMMARYNewly developed interferon-gamma release assays have become commercially available to detect tuberculosis (TB) infection in adults. However, little is known about their performance in children. We compared test results between the QuantiFERON-TB® Gold test (QFT) and tuberculin skin test (TST) in young children living with pulmonary TB patients in Cambodia. Of 195 children tested with both QFT and TST, the TST-positive rate of 24% was significantly higher than the QFT-positive rate of 17%. The agreement between the test results was considerable (κ-coefficient 0·63). Positive rates increased from 6% to 32% for QFT and from 15% to 43% for TST, according to the sputum smear grades of the index cases. The presence of Bacille Calmette-Guérin (BCG) scars did not significantly affect the results of TST or QFT in a logistic regression analysis. In conclusion, QFT can be a substitute for TST in detecting latent TB infection in childhood contacts aged ⩽5 years, especially in those who may have a false-positive TST due to BCG vaccination or non-tuberculous mycobacterial infection.


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