Prevalence and risk factors of latent tuberculosis among Korean healthcare workers using whole-blood interferon-γ release assay

This study established the diagnosis and risk factors of latent tuberculosis infection (LTBI) among health-care workers in an endemic population using Tuberculin skin test (TST) and Quantiferon TB-gold. A total of 609 Healthcare workers from tuberculosis treatment facilities in Akwa Ibom State, Nigeria were studied. The Interferon-gamma release assay was performed using 3ml of whole blood by ELISA according to the manufacturer’s instruction (Cellestis Ltd., Carnegie, Australia) after which 0.1 ml of 5 tuberculin units of Purified Protein Derivative (PPD) was administered intra-dermally to each subject. TST results were read after 72 hours by measuring the size of indurations in millimetres. Data were analysed using SPSS version 17 (SPSS Inc., Chicago, Illinois). At the threshold of 10 mm, the prevalence of LTBI by TST was 45.8% and 24.8% at the IGRA diagnostic value of ≥ 0.351 IU. Laboratory staff and ward orderlies as well as being in service for >10 years, were more significantly associated with LTBI. A moderate agreement of 76.7%, k = 0.51 was obtained between TST at 10 mm, and QFT. Neither previous exposure to TST nor BCG vaccination affected the prevalence of LTBI in the study population. The difference of 54% prevalence of LTBI between TST and QFT may be due to non-tuberculous mycobacterium (NTM) since TST is non-specific. This may have grave implications of drug toxicity and development of resistance to anti-TB drug among individuals harbouring NTM, but receiving anti-TB medication. The 76.7% agreement between the two tests is an indication that the 10 mm cut-off induration for TST is still relevant in the diagnosis of LTBI.

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Prevalence and Risk Factors of Latent Tuberculosis Infection among Healthcare Workers Using Tuberculin Skin Test and Interferon-γ Release Assay at a Tertiary Hospital in South Korea

Korean Journal of Healthcare-Associated Infection Control and Prevention ◽

10.14192/kjicp.2020.25.1.46 ◽

2020 ◽

Vol 25 (1) ◽

pp. 46-53

Author(s):

Sin Jeong Kim ◽

Eunjin Ha ◽

Eun Suk Park ◽

Jun Young Choi ◽

Young Ae Kang

Keyword(s):

Risk Factors ◽

South Korea ◽

Tuberculin Skin Test ◽

Skin Test ◽

Healthcare Workers ◽

Latent Tuberculosis Infection ◽

Latent Tuberculosis ◽

Tertiary Hospital ◽

Interferon Γ ◽

Release Assay

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Use of a T Cell Interferon-γ Release Assay to Evaluate Tuberculosis Risk in Newly Qualified Physicians in Singapore Healthcare Institutions

Infection Control and Hospital Epidemiology ◽

10.1086/599284 ◽

2009 ◽

Vol 30 (9) ◽

pp. 870-875 ◽

Cited By ~ 13

Author(s):

C. B. E. Chee ◽

L. K. Y. Lim ◽

T. M. Barkham ◽

D. R. Koh ◽

S. O. Lam ◽

...

Keyword(s):

Healthcare Workers ◽

Latent Tuberculosis ◽

Risk Groups ◽

Interferon Γ ◽

Public Hospitals ◽

High Rate ◽

Assay Result ◽

Release Assay ◽

Baseline Test ◽

Tuberculosis Risk

Background.Surveillance for latent tuberculosis in high-risk groups such as healthcare workers is limited by the nonspecificity of the tuberculin skin test (TST) in BCG-vaccinated individuals. The Mycobacterium tuberculosis antigen-specific interferon-γ release assays (IGRAs) show promise for more accurate latent tuberculosis detection in such groups.Objective.To compare the utility of an IGRA, the T-SPOT.TB assay, with that of the TST in healthcare workers with a high rate of BCG vaccination.Methods.Two hundred seven medical students from 2 consecutive cohorts underwent the T-SPOT.TB test and the TST in their final year of study. Subjects with negative baseline test results underwent repeat testing after working for 1 year as junior physicians in Singapore's public hospitals.Results.The baseline TST result was an induration 10 mm or greater in diameter in 177 of the 205 students who returned to have their TST results evaluated (86.3%), while the baseline T-SPOT.TB assay result was positive in 9 (4.3%) of the students. Repeat T-SPOT.TB testing in 182 baseline-negative subjects showed conversion in 9 (4.9%). A repeat TST in 18 subjects with baseline-negative TST results did not reveal any TST result conversion.Conclusions.The high rate of positive baseline TST results in our BCG-vaccinated healthcare workers renders the TST unsuitable as a surveillance tool in this tuberculosis risk group. Use of an IGRA has enabled the detection and treatment of latent tuberculosis in this group. Our T-SPOT.TB conversion rate highlights the need for greater tuberculosis awareness and improved infection control practices in our healthcare institutions.

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Does the Implementation of an Interferon-γ Release Assay in Lieu of a Tuberculin Skin Test Increase Acceptance of Preventive Therapy for Latent Tuberculosis Among Healthcare Workers?

Infection Control and Hospital Epidemiology ◽

10.1086/593965 ◽

2009 ◽

Vol 30 (2) ◽

pp. 197-199 ◽

Cited By ~ 13

Author(s):

Rajiv Sahni ◽

Cyndee Miranda ◽

Belinda Yen-Lieberman ◽

J. Walton Tomford ◽

Paul Terpeluk ◽

...

Keyword(s):

Tuberculin Skin Test ◽

Skin Test ◽

Healthcare Workers ◽

Latent Tuberculosis ◽

Interferon Γ ◽

Preventive Therapy ◽

Release Assay ◽

Test Increase

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Discordant QuantiFERON-TB Gold Test Results Among US Healthcare Workers With Increased Risk of Latent Tuberculosis Infection: A Problem or Solution?

Infection Control and Hospital Epidemiology ◽

10.1086/590262 ◽

2008 ◽

Vol 29 (9) ◽

pp. 878-886 ◽

Cited By ~ 40

Author(s):

Nira R. Pollock ◽

Antonio Campos-Neto ◽

Suely Kashino ◽

Danielle Napolitano ◽

Samuel M. Behar ◽

...

Keyword(s):

Healthcare Workers ◽

Latent Tuberculosis Infection ◽

Latent Tuberculosis ◽

Interferon Γ ◽

Tuberculosis Infection ◽

Test Results ◽

Negative Results ◽

Increased Risk ◽

Release Assay ◽

Positive Results

Objective.In late 2006, our hospital implemented use of the QuantiFERON-TB Gold (QFT-G) assay, a whole-blood interferon-γ release assay, for detection of tuberculosis infection. All newly hired healthcare workers (HCWs) with positive Mantoux tuberculin skin test (TST) results were routinely tested with the QFT-G assay, to take advantage of its higher specificity. We then undertook a quality assurance review to evaluate the QFT-G test results in HCWs with multiple risk factors for latent tuberculosis infection (LTBI).Methods.The clinical records for TST-positive HCWs tested with the QFT-G assay were reviewed. HCWs with 2 or more risk factors commonly associated with LTBI were classified as “increased risk” (IR). IR HCWs who had negative QFT-G test results underwent repeat QFT-G testing and were offered testing with a different interferon-γ release assay (T-SPOT.TB) and with extended T cell stimulation assays.Results.Ofl43 TST-positive HCWs tested with the QFT-G assay, 26 (18%) had positive results, 115 (81%) had negative results, and 2 (1 %) had indeterminate results. Of 82 IR HCWs, 23 (28%) had positive QFT-G test results, and 57 (70%) had negative results. Of the 57 IR HCWs with negative results, 43 underwent repeat QFT-G testing: 41 had negative results again, and 2 had positive results. These 43 HCWs were also offered additional testing with the T-SPOT.TB diagnostic, and 36 consented: 31/36 tested negative, and 5/36 tested positive. Extended assays using the antigens ESAT-6 and CFP-10 confirmed the positive results detected by the overnight assays and yielded positive results for an additional 7/36 (19%) of individuals; strikingly, all 36 HCWs had strongly positive test results with assays using purified protein derivative.Conclusions.The extreme discordance between the results of our clinical diagnostic algorithm and the results of QFT-G testing raises concern about the sensitivity of the QFT-G assay for detection of LTBI in our HCWs. Results of extended stimulation assays suggest that many of our IR HCWs have indeed been sensitized to Mycobacterium tuberculosis. It is possible that the QFT-G assay identifies those at higher reactivation risk rather than all previously infected, but, in the absence of long-term follow-up data, we should interpret negative QFT-G results with some caution.

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Screening for latent tuberculosis infection in South Korean healthcare workers using a tuberculin skin test and whole blood interferon-γ assay

Scandinavian Journal of Infectious Diseases ◽

10.3109/00365548.2010.485575 ◽

2010 ◽

Vol 42 (9) ◽

pp. 672-678 ◽

Cited By ~ 14

Author(s):

Kyung Jong Lee ◽

Young Ae Kang ◽

Young Mi Kim ◽

Sang-Nae Cho ◽

Jin Wook Moon ◽

...

Keyword(s):

Tuberculin Skin Test ◽

Skin Test ◽

Whole Blood ◽

Healthcare Workers ◽

Latent Tuberculosis Infection ◽

Latent Tuberculosis ◽

Interferon Γ ◽

Tuberculosis Infection ◽

South Korean

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Detection of latent tuberculosis by the tuberculin skin test and a whole-blood interferon-γ release assay, and the development of active tuberculosis in HIV-seropositive persons

Diagnostic Microbiology and Infectious Disease ◽

10.1016/j.diagmicrobio.2010.09.005 ◽

2011 ◽

Vol 69 (1) ◽

pp. 59-65 ◽

Cited By ~ 21

Author(s):

Miguel Santin ◽

Susana Casas ◽

Maria Saumoy ◽

Ana Andreu ◽

Raquel Moure ◽

...

Keyword(s):

Tuberculin Skin Test ◽

Skin Test ◽

Whole Blood ◽

Latent Tuberculosis ◽

Interferon Γ ◽

Active Tuberculosis ◽

Release Assay ◽

Hiv Seropositive

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The Effect of Previous Tuberculin Skin Test on the Follow-up Examination of Whole-Blood Interferon-γ Assay in the Screening for Latent Tuberculosis Infection

CHEST Journal ◽

10.1378/chest.07-2193 ◽

2008 ◽

Vol 133 (6) ◽

pp. 1415-1420 ◽

Cited By ~ 50

Author(s):

Jae Chol Choi ◽

Jong Wook Shin ◽

Jae Yeol Kim ◽

In Won Park ◽

Byoung Whui Choi ◽

...

Keyword(s):

Tuberculin Skin Test ◽

Skin Test ◽

Whole Blood ◽

Latent Tuberculosis Infection ◽

Latent Tuberculosis ◽

Interferon Γ ◽

Tuberculosis Infection

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754. Prevalence of Latent Tuberculosis Infection Among Healthcare Workers at a Tertiary Care University Hospital

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.761 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S271-S271

Author(s):

Eun Ju Choo ◽

Se Yoon Park

Keyword(s):

Risk Factors ◽

Healthcare Workers ◽

Latent Tuberculosis Infection ◽

Tertiary Care ◽

Latent Tuberculosis ◽

Tuberculosis Infection ◽

University Hospital ◽

Increased Risk ◽

High Prevalence ◽

Univariate Analyses

Abstract Background We investigated the prevalence of latent tuberculosis infection (LTBI) among healthcare workers (HCWs) and analyzed its risk factors in a tertiary care university hospital in South Korea in a population with intermediate tuberculosis (TB) burden. Methods A standard questionnaire regarding the baseline demographics and risk factors for LTBI was given to each participant. QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay and chest radiography were performed to investigate the rate of LTBI. Results A total of 1,429 participants, 213 (14.9%) doctors and 988 (69.1%) nurses and 228 (16.0%) others were enrolled. The mean age of the subjects was 33.0 years old, and 1,175 (82.2%) were female. Of the participants, 94.5% had received BCG vaccine. QFT-GIT assays were positive for 156 subjects (10.9%). Of the 213 doctors, 28 (13.1%) were positive by QFT-GIT, and among the 988 nurses, 94 (9.5%) had positive QFT-GIT results. Experience of working in hospital was significantly associated with positive LTBI test results by QFT-GIT assay. Gender and duration of employment as an HCW were significantly associated with having a positive QFT-GIT result in univariate analyses. In multivariate analyses, duration of employment as an HCW (>15 years) (odds ratio, 1.98; 95% confidence interval, 1.14–3.43) was independently associated with increased risk of a positive QFT-GIT result. Conclusion A high prevalence of LTBI was found among our HCWs. Considering the association between the experience of working in hospital and high risk of LTBI. The risk for tuberculosis infection among HCWs was higher than general population, which suggests that stricter preventive strategies against nosocomial tuberculosis infection should be implemented. Disclosures All authors: No reported disclosures.

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