QuantiFERON-TB Gold In-Tube as a Confirmatory Test for Tuberculin Skin Test in Tuberculosis Contact Tracing: A Noninferiority Clinical Trial.

Background: Screening strategies based on interferon-γ release assays in tuberculosis contact tracing may reduce the need for preventive therapy without increasing subsequent active disease. Methods: We conducted an open-label, randomized trial to test the noninferiority of a 2-step strategy with the tuberculin skin test (TST) followed by QuantiFERON-TB Gold In-Tube (QFT-GIT) as a confirmatory test (the TST/QFT arm) to the standard TST-alone strategy (TST arm) for targeting preventive therapy in household contacts of patients with tuberculosis. Participants were followed for 24 months after randomization. The primary endpoint was the development of tuberculosis, with a noninferiority margin of 1.5 percentage points. Results: A total of 871 contacts were randomized. Four contacts in the TST arm and 2 in the TST/QFT arm developed tuberculosis. In the modified intention-to-treat analysis, this accounted for 0.99% in the TST arm and 0.51% in the TST/QFT arm (-0.48% difference; 97.5% confidence interval [CI], -1.86% to 0.90%); in the per-protocol analysis, the corresponding rates were 1.67% and 0.82% in the TST and TST/QFT arms, respectively (-0.85% difference; 97.5% CI, -3.14% to 1.43%). Of the 792 contacts analyzed, 65.3% in the TST arm and 42.2% in the TST/QFT arm were diagnosed with tuberculosis infection (23.1% difference; 95% CI, 16.4% to 30.0%). Conclusions: In low-incidence settings, screening household contacts with the TST and using QFT-GIT as a confirmatory test is not inferior to TST-alone for preventing active tuberculosis, allowing a safe reduction of preventive treatments. Clinical Trials Registration: NCT01223534.

Executive summary of the guidelines for the use of interferon-γ release assays in the diagnosis of tuberculosis infection.

Interferon-gamma release assays are widely used for the diagnosis of tuberculosis infection in Spain. However, there is no consensus on their application in specific clinical scenarios. To develop a guideline for their use, a panel of experts comprising specialists in infectious diseases, respiratory diseases, microbiology, pediatrics and preventive medicine, together with a methodologist, conducted a systematic literature search, summarized the findings, rated the quality of the evidence, and formulated recommendations following the GRADE (Grading of Recommendations of Assessment Development and Evaluations) methodology. This document provides evidence-based guidance on the use of interferon-gamma release assays for the diagnosis of tuberculosis infection in patients at the risk of tuberculosis or suspected of having active disease. The guidelines will be applicable to specialist and primary care, and public health.

Executive Summary of the Guidelines for the Use of interferon-gamma Release Assays in the Diagnosis of Tuberculosis Infection. / Sumario ejecutivo de la guía de práctica clínica sobre el uso de las pruebas de liberación de interferón-gamma para el diagnóstico de infección tuberculosa.

Interferon-gamma release assays are widely used for the diagnosis of tuberculosis infection in Spain. However, there is no consensus on their application in specific clinical scenarios. To develop a guide-line for their use, a panel of experts comprising specialists in infectious diseases, respiratory diseases, microbiology, pediatrics and preventive medicine, together with a methodologist, conducted a systematic literature search, summarized the findings, rated the quality of the evidence, and formulated recommendations following the Grading of Recommendations of Assessment Development and Evaluations methodology. This document provides evidence-based guidance on the use of interferon-gamma release assays for the diagnosis of tuberculosis infection in patients at risk of tuberculosis or suspected of having active disease. The guidelines will be applicable to specialist and primary care, and public health.