0
Chest Infections |

Performance and Practicality of IGRA in Serial Testing for Latent TB Infection in US Healthcare Workers - A Real World Experience

Manish Joshi*, MD; Thomas Monson, MD; Gail Woods, MD
Author and Funding Information

Central Arkansas Veterans Healthcare System, Little Rock, AR


Chest. 2012;142(4_MeetingAbstracts):142A. doi:10.1378/chest.1386337
Text Size: A A A
Published online

Abstract

SESSION TYPE: TB and NTM

PRESENTED ON: Sunday, October 21, 2012 at 01:15 PM - 02:45 PM

PURPOSE: To assess Quantiferon Gold In-Tube (QFT) assay feasibility, conversions, and reversions in US healthcare workers (HCWs) and compare it with Tuberculin skin test (TST)

METHODS: We identified a HCW cohort at Central Arkansas Veterans Healthcare System (CAVHS) and presented the performance of QFT for initial LTBI testing at CHEST 2010. We retrospectively followed this cohort and analyzed the serial testing results performed after a period of 1 year. We also compared these QFT results with serial TSTs performed prior to QFT 1 and after QFT 2 tests. QFT was performed as per manufacturer's instructions. QFT Conversions were defined as baseline negative results (IFN-γ values <0.35 IU/ml) which became positive on follow up testing. QFT Reversions were defined as initial positive tests (IFN-γ values ≥0.35 IU/ml) which became negative on follow-up testing. TSTs were performed and interpreted by experienced nurses in CAVHS employee health as per CDC guidelines. TSTconversion was defined as an induration ≥10 mm and an increase of ≥10 mm from baseline value as per CDC guidelines.

RESULTS: Of the total 2303 HCWs, 69 were QFT-positive at baseline and 2 were indeterminate. 31/69 (45%) of these HCWs reverted on repeat testing. 25/31(80.6%) HCWs that reverted had a negative baseline TST. Of the 2232 HCWs with baseline QFT-negative results, 71 (3.2%) converted on repeat testing but only 2 HCWs had concordant TST conversion. A third QFT assay was performed in 41 out of these 71 new converters and 90% (37/41) reverted back to negative.

CONCLUSIONS: 1. The QFT is feasible in a large academic tertiary healthcare setting. 2. The QFT conversion rates were very high (>30 times) compared to the baseline TST conversion rates in our institution in the preceding 5 years. However 90% of those new converters who were retested reverted back on repeat QFT testing, suggesting that they were likely false conversions. 3. QFT has poor performance and reproducibility in serial testing of HCW's in the US considering the high conversion and reversion rates associated with the test.

CLINICAL IMPLICATIONS: 1. Our results suggest caution in interpreting QFT results in the serial testing of HCWs in US. 2. Repeat testing and/or TST is suggested for new converters. 3. Healthcare institutions should consider QFT variability, poor short and long term reproducibility, and cost before implementing the test.

DISCLOSURE: The following authors have nothing to disclose: Manish Joshi, Thomas Monson, Gail Woods

No Product/Research Disclosure Information

Central Arkansas Veterans Healthcare System, Little Rock, AR

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Figures

Tables

References

NOTE:
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.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Related Content

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

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