SMF Schweizerisches Medizin-Forum 1424-4020 1424-3784 EMH Schweizerischer Ärzteverlag AG Farnsburgerstrasse 8 CH-4132 Muttenz 08569 10.4414/smf.2021.08569 Wie deuten Sie diesen Befund? Allergologie / Immunologie Infektiologie Labormedizin «Interferon Gamma Release Assays» ou IGRA Truong Minh Khoa Minh-Khoa.Truong@chuv.ch Médecine | Rue du Bugnon 46 | Lausanne | Vaud | 1011 | SWITZERLAND | +41792563515 Nicod Laurent laurent.nicod@chuv.ch CHUV, Service de pneumologie Mazza-Stalder Jesica jesica.mazza-stalder@chuv.ch CHUV, service de pneumologie Aubert Vincent vincent.aubert@chuv.ch CHUV, Laboratoire d'immunologie et allergie Vollenweider Peter peter.vollenweider@chuv.ch CHUV, Service de médecine interne 16 02 2021 21 0708 128 131 Copyright: EMH Schweizerischer Ärzteverlag AG 2021 EMH Schweizerischer Ärzteverlag AG "Swiss Medical Forum" is an open access publication of EMH published in accordance with the terms of the Creative Commons licence attribution - NonCommercial - NoDerivatives 4.0 International. You are free to share, copy and redistribute the material in any medium or format under the following terms: Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. NonCommercial — You may not use the material for commercial purposes. NoDerivatives — If you remix, transform, or build upon the material, you may not distribute the modified material. "Non-commercial" means not primarily intended for or directed towards commercial advantage or monetary compensation. The incorporation of publications in commercial products, the use of publications to advertise for commercial products or services and any other usage that directly or indirectly pursues commercial interests is subject to the express previous consent of the publishing house as part of a written agreement. Please send us your request in writing. Exact indication of the publication from which you would like to reproduce material and detailed information about its intended use help to facilitate and expedite request processing.

Introduction WHO estimates latent tuberculosis infection (LTBI) prevalence at 1.7 billion cases, which equals approximately one quarter of the world’s population. Strategy to control tuberculosis includes early detection and treatment of potentially contagious patients.   Discussion IGRAs are in vitro blood tests that measure T cell-mediated immune response to Mycobacterium tuberculosis . Available IGRAs are T-SPOT.TB and QuantiFERON-TB, with both first and second generations Gold In-Tube (QFT-GIT) and Gold Plus (QFT-Plus). IGRAs have sensibility ranging from 81% to 94% and specificity over 95%. A majority of patients (>95%) with positive IGRA results do not progress to active tuberculosis. Therefore, IGRAs should only be used with patients for whom a treatment of LTBI is planned should the test result come out positive. This includes contacts of cases of infectious tuberculosis, HIV-infected patients, patients undergoing immunosuppressive treatment or dialysis for chronic renal failure, and patients with silicosis. IGRAs should not be used to distinguish between LTBI and active tuberculosis.   Conclusion IGRAs are the first choice exam in Switzerland for detecting LTBI. Their use require good knowledge of the test characteristics, indications and limitations