Use of a Gamma-IFN Assay in Contact Tracing for Tuberculosis in a Low-Incidence, High Immigration Area

Completed

• Conditions: Tuberculosis; Latent Tuberculosis Infection

• Registration Number: NCT00557765
• Lead Sponsor: University Hospital, Geneva

Brief Summary

After exposure to an active case of tuberculosis (TB), close contacts may be infected. They are then considered as having latent tuberculosis infection (LTBI). Detecting LTBI is the main goal of contact tracing procedures after exposure to TB. Until recently, the only test available for detecting LTBI was the tuberculin skin test (TST). More recent tests are now available (Interferon-gamma release assays: IGRA), which are more specific and sensitive than the TST. This study compares the TST and an IGRA in the routine activity of contact tracing in our area.

Detailed Description

Setting: A TB clinic in Geneva, Switzerland, a low incidence area for TB with a high immigrant population.

Aim of study: to compare results of an IGRA test (T-SPOT.TB, Oxford Immunotec, UK) and the TST, and their correlation with exposure scores in subjects exposed to cases of contagious TB.

Methods: Prospective study of all contacts screened in our area, and accepting to be included. Simultaneous recording of age, gender, origin, history of recent travels or exposure, BCG vaccination status, infectiousness of index case, 5 different exposure scores, TST, and result of the T-SPOT.TB blood test. Univariate and multivariate analysis.

Study Timeline

• Study Start: 2004-10
• Study Completion: 2006-01
• Status Verified: 2007-11
• Study First Submitted: 2007-11-13
• Study First Submitted QC: 2007-11-13
• Last Update Submitted: 2007-11-13
• Study First Posted: 2007-11-14
• Last Update Posted: 2007-11-14

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 295

Inclusion Criteria

• Exposure to a case of contagious TB
• Willingness to participate in study

Exclusion Criteria

• Known HIV infection
• Known previous TB or treatment for LTBI

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Correlation between results of TST and IGRA tests and exposure scores	2 months after exposure

Trial Locations

Locations (1)

Centre antituberculeux; Geneva University Hospital; 🇨🇭 Geneva, Switzerland