Diagnosis of Tuberculosis Infection in Health Care Workers Using Ex-vivo Interferon-gamma Assay

Study Overview
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Brief Summary
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The present study was to evaluate the usefulness of a whole-blood interferon-r release assays (IGRAs) as diagnostic tool of the latent tuberculosis infection for healthcare workers.

Official Title
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Diagnosis of Tuberculosis Infection in Health Care Workers Using Ex-vivo Interferon-gamma Assay

Conditions
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Latent Tuberculosis Infection

Intervention / Treatment
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* Other: 1-step tuberculin skin test (TST) and blood sampling


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: doctors and nurses newly hired at Samsung Medical Center between February, 2008 and November, 2008. Exclusion Criteria: Non-applicable
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: new healthcare workers<br>doctors and nurses who were newly hired in 2008 at the Samsung Medical Center | Other: 1-step tuberculin skin test (TST) and blood sampling<br>* In only new healthcare workers, the 1-step TST and quantiFERON-TB Gold In-Tube test were performed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Annual Incidence of Tuberculosis Infection Among Newly Employed Doctors and Nurses in Korea | The participants performed QuaniFERON-TB Gold In-Tube test (QFT-IT test). Annual infection of tuberculosis infection was evaluated with the conversion of QFT-IT test through annual check up of QFT-IT test. The definitions for QFT-IT test conversion was based on the CDC definition (Baseline IFN-r < 0.35 IU/ml and follow-up IFN-r ≥ 0.35 IU/ml). | QFT-IT test was performed at enrollment and repeated at point of one year after enrollment. So, the length of timw which from the start of the first test of very first participant to the end of second test of very last participant is 2 years. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Negative Conversion Rate in Follow-up QuantiFERON-TB Gold In-Tube Test (QFT-IT Test) After Treatment of Latent Tuberculosis Infection (LTBI) | The percentage of participants with negative conversion in follow-up QFT-IT test after LTBI treatment, out of those who had QFT-IT test conversion after one year of employment and agreed to undergo treatment for LTBI according to our recommendation Participants with QFT-IT test conversion were recommended for LTBI therapy using 3 months of daily isoniazid and rifampicin, which was the regular treatment for LTBI in our institution. The QFT-IT test was repeated after LTBI therapy. Negative conversion was defined as baseline IFN-r ≥ 0.35 and follow-up IFN-r < 0.35 IU/ml. | 3 months after LTBI treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Interferon-gamma release assay