Refining the diagnostic approach to latent tuberculosis Infection with Quantiferon gold plus: A retrospective analysis of borderline results.

ABSTRACT: The Quantiferon Gold Plus (QFT) test, a widely used interferon-γ release assay (IGRA), diagnoses latent tuberculosis infection (LTBI) with a positivity threshold of ≥0.35 IU/mL. Results near this cut-off can be challenging to interpret due to variability from immunological, pre-analytical, and technical factors, prompting recommendations for a borderline range to refine diagnosis and reduce overtreatment. This retrospective study analyzed QFT results from 9,944 patients (2019-2023), establishing ranges: < 0.2 IU/mL as negative, 0.2-0.35 IU/mL as borderline negative, 0.35-0.7 IU/mL as borderline positive, and >0.7 IU/mL as positive. Borderline results occurred in 7.6% of patients, particularly in those born in Africa or South America, and in older individuals. Of 64 patients retested, 60.9%

SUBMITTER: Ruedas-Lopez A 

PROVIDER: S-EPMC12416684 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature