Questionable Effectiveness of the QuantiFERON-TB Gold Test (Cellestis) as a Screening Tool in Healthcare Workers

Gandra, Sumanth; Scott, W. P.; Somaraju, Vijaya; Wang, Huaping; Wilton, Suzanne; Feigenbaum, Michelle

doi:10.1086/657336

Cited by 40 publications

(33 citation statements)

References 9 publications

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“…Overall, repeat results were more likely to be lower than initial results (overall average mean difference: 20.18; 95% CI, 20.23 to 20.13), which partially explained the large number of reversions with retesting. To assess whether this was due to a regressionto-the-mean phenomenon, an analysis was SYSTEMATIC REVIEW done excluding studies that only repeated tests when the initial result was positive (4,5,31). In this subanalysis, the total number of reversions decreased to 5.5% (19 of 344) and the kappa statistic for agreement between the baseline and first repeat measurement increased to 0.75 (95% CI, 0.61-0.88), suggesting that a regressionto-the-mean phenomenon was present.…”

Section: Quantiferon Variability Under Different Conditionsmentioning

confidence: 99%

“…However, there is uncertainty about the interpretation of results when IGRAs are performed serially in subgroups with very low annual risk of tuberculosis infection, including in health-care workers. Conversions (change from negative to positive test results) and reversions (change from positive to negative test results) have been reported to occur more commonly for IGRAs than skin test (3)(4)(5)(6)(7)(8). Uncertainty in the interpretation of repeat results has also been reported for the skin test.…”

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confidence: 99%

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Reproducibility of Interferon Gamma (IFN-γ) Release Assays. A Systematic Review

Tagmouti¹,

Slater

Benedetti

et al. 2014

Annals ATS

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Rationale: Interferon gamma (IFN-g) release assays for latent tuberculosis infection result in a larger-than-expected number of conversions and reversions in occupational screening programs, and reproducibility of test results is a concern.Objectives: Knowledge of the relative contribution and extent of the individual sources of variability (immunological, preanalytical, or analytical) could help optimize testing protocols. Methods:We performed a systematic review of studies published by October 2013 on all potential sources of variability of commercial IFN-g release assays (QuantiFERON-TB Gold In-Tube and T-SPOT.TB). The included studies assessed test variability under identical conditions and under different conditions (the latter both overall and stratified by individual sources of variability). Linear mixed effects models were used to estimate withinsubject SD. Measurements and Main Results:We identified a total of 26 articles, including 7 studies analyzing variability under the same conditions, 10 studies analyzing variability with repeat testing over time under different conditions, and 19 studies reporting individual sources of variability. Most data were on QuantiFERON (only three studies on T-SPOT.TB). A considerable number of conversions and reversions were seen around the manufacturer-recommended cut-point. The estimated range of variability of IFN-g response in QuantiFERON under identical conditions was 60.47 IU/ml (coefficient of variation, 13%) and 60.26 IU/ml (30%) for individuals with an initial IFN-g response in the borderline range (0.25-0.80 IU/ml). The estimated range of variability in noncontrolled settings was substantially larger (61.4 IU/ml; 60%). Blood volume inoculated into QuantiFERON tubes and preanalytic delay were identified as key sources of variability.Conclusions: This systematic review shows substantial variability with repeat IFN-g release assays testing even under identical conditions, suggesting that reversions and conversions around the existing cut-point should be interpreted with caution.

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Section: Quantiferon Variability Under Different Conditionsmentioning

confidence: 99%

mentioning

confidence: 99%

Reproducibility of Interferon Gamma (IFN-γ) Release Assays. A Systematic Review

Tagmouti¹,

Slater

Benedetti

et al. 2014

Annals ATS

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“…When switching from annual TST screening to annual IGRA screening in a country with low risk of exposure to infectious TB patients or materials and low BCG vaccination rate, discordant test results, that is, actual positive IGRA and negative TST results in the past, might occur as described by Gandra et al [74]. Out of 6530 HCWs tested with IGRA, 287 (4.4%) were positive and, out of these 287 HCW, 164 (57.1%) had a negative TST in the past.…”

Section: The Effect Of Introducing Igra In Tb Screening Of Hcwmentioning

confidence: 99%

IFN-γ release assay versus tuberculin skin test for monitoring TB infection in healthcare workers

Nienhaus

Ringshausen

Costa³

et al. 2013

Expert Review of Anti-infective Therapy

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“…16,17 Serial testing of health care workers at low risk of infection has often revealed unexplained conversion of IGRA results to positive and reversion to negative. Nkurunungi et al 18 performed T-SPOT tests on 405 Ugandan children at age 5 years and then repeated the test 3 weeks later.…”

Section: Test Characteristicsmentioning

confidence: 99%

Interferon-γ Release Assays for Diagnosis of Tuberculosis Infection and Disease in Children

Starke¹,

Byington²,

Barnett³

et al. 2014

Pediatrics

143

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Tuberculosis (TB) remains an important problem among children in the United States and throughout the world. Although diagnosis and treatment of infection with Mycobacterium tuberculosis (also referred to as latent tuberculosis infection [LTBI] or TB infection) remain the lynchpins of TB prevention, there is no diagnostic reference standard for LTBI. The tuberculin skin test (TST) has many limitations, including difficulty in administration and interpretation, the need for a return visit by the patient, and false-positive results caused by significant cross-reaction with Mycobacterium bovis-bacille CalmetteGuérin (BCG) vaccines and many nontuberculous mycobacteria. Interferon-γ release assays (IGRAs) are blood tests that measure ex vivo T-lymphocyte release of interferon-γ after stimulation by antigens specific for M tuberculosis. Because these antigens are not found on M bovis-BCG or most nontuberculous mycobacteria, IGRAs are more specific tests than the TST, yielding fewer false-positive results. However, IGRAs have little advantage over the TST in sensitivity, and both methods have reduced sensitivity in immunocompromised children, including children with severe TB disease. Both methods have a higher positive predictive value when applied to children with risk factors for LTBI. Unfortunately, neither method distinguishes between TB infection and TB disease. The objective of this technical report is to review what IGRAs are most useful for: (1) increasing test specificity in children who have received a BCG vaccine and may have a falsepositive TST result; (2) using with the TST to increase sensitivity for finding LTBI in patients at high risk of developing progression from LTBI to disease; and (3) helping to diagnose TB disease. Pediatrics

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Questionable Effectiveness of the QuantiFERON-TB Gold Test (Cellestis) as a Screening Tool in Healthcare Workers

Abstract: The disagreement between QFT-GIT and TST results and the high reversion rate with QFT-GIT raise concerns about the effectiveness of QFT-GIT as a sole screening test in HCWs.

Cited by 40 publications

References 9 publications

Reproducibility of Interferon Gamma (IFN-γ) Release Assays. A Systematic Review

Reproducibility of Interferon Gamma (IFN-γ) Release Assays. A Systematic Review

IFN-γ release assay versus tuberculin skin test for monitoring TB infection in healthcare workers

Interferon-γ Release Assays for Diagnosis of Tuberculosis Infection and Disease in Children

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