Slide Presentations: Monday, November 1, 2010 |

Practical Experience With the QFT-GIT Assay for LTBI Annual Testing Among US Health-care Workers in a Large Tertiary Setting FREE TO VIEW

Manish Joshi, MD; Thomas P. Monson, MD; Gail L. Woods, MD
Author and Funding Information

Central Arkansas VA healthcare system, Little Rock, AR

Chest. 2010;138(4_MeetingAbstracts):746A. doi:10.1378/chest.9384
Text Size: A A A
Published online


PURPOSE: To asess Performance and Practicality of QuantiFERON-TB Gold In-Tube(QFT-GIT)assay for the detection of LTBI in US healthcare workers (HCW)in large healthcare setting.

METHODS: Retrospective chart review of all CAVHS (Central Arkansas VA Healthcare syatem)healthcare workers who underwent QFT-GIT testing as a part of annual employee screening to detect LTBI from 11/08 to 10/09. Protocol was approved by CAVHS IRB. Specific variables collected were QFT-GIT results and prior or concurrent TST (Tuberculin Skin test)Readings. The QFT-GIT test was performed according to the manufacturer’ s instructions(Cellestis Ltd, Carnegie, Australia)with a cutoff value for a positive test of IFN-g of 0.35 IU/ml or greater. Some tests were repeated (positive and indeterminate)and repeat readings were recorded as final readings for indeterminate tests for this study purposes. TST’ s were performed and/or reported in Electronic Medical Records(EMR) of CAVHS. For this study, negative TST was <5mm induration after 48-72hrs of TST placement.

RESULTS: 3290 healthcare workers underwent QFT-GIT testing from 11/08 to 10/09, 3380 tests were performed. 129/3290 were reported positive, 3155 negative and 6 were indeterminate. 45 HCW with positive tests underwent repeat testing, median 2 weeks(range 1-8 weeks)and 18/45 (40%) were reported negative. There was overall good agreement between QFT-GIT and TST(>99%), however positive tests in each category showed huge discordance (>50%).

CONCLUSION: 1. QFT-GIT is feasible in large healtcare setting as an alternate to TST for annual LTBI screening in healthcare workers. 2. The short term reproducibility of positive QFT-GIT tests is poor. 3. There is large discordance among positive tests (TST and QFT-GIT). Superiority/higher predictive value of one test over the other can’ t be estimated as there is no gold standard to detect LTBI.

CLINICAL IMPLICATIONS: 1. Our study suggests that all positive QFT-GIT tests,as a part of annual employee screening in HCW to detect LTBI, upto values of 2 IU/mL should be confirmed by repeat testing. 2. More long term studies are needed to assess long term reproducibility and predictive value.

DISCLOSURE: Manish Joshi, No Financial Disclosure Information; No Product/Research Disclosure Information

08:00 AM - 09:15 AM




Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543