title: Interferon Gamma Release Assays for Latent Tuberculosis: What Are the Sources of Variability?
abstract: Interferon gamma release assays (IGRAs) are blood-based tests intended for diagnosis of latent tuberculosis infection (LTBI). IGRAs offer logistical advantages and are supposed to offer improved specificity over the tuberculin skin test (TST). However, recent serial testing studies of low-risk individuals have revealed higher false conversion rates with IGRAs than with TST. Reproducibility studies have identified various sources of variability that contribute to nonreproducible results. Sources of variability can be broadly classified as preanalytical, analytical, postanalytical, manufacturing, and immunological. In this minireview, we summarize known sources of variability and their impact on IGRA results. We also provide recommendations on how to minimize sources of IGRA variability.
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, USA Clinical Microbiology Laboratory, Stanford Health Care, Stanford, California, USA nbanaei@stanford.edu.
authors.forename: Niaz
authors.initials: N
authors.lastname: Banaei
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Rajiv L
authors.initials: RL
authors.lastname: Gaur
authors.affiliation: McGill International TB Centre and Department of Epidemiology & Biostatistics, McGill University, Montreal, Quebec, Canada.
authors.forename: Madhukar
authors.initials: M
authors.lastname: Pai
mesh_terms: D003955:Diagnostic Tests, Routine / Q000379:methods*; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000379:methods*; D055985:Latent Tuberculosis / Q000175:diagnosis*; D015203:Reproducibility of Results