Testing for Mycobacterium tuberculosis infection using the QuantiFERON-TB GOLD assay in patients with comorbid conditions in a tertiary care endemic setting

Tropical Diseases, Travel Medicine and Vaccines

Bushra Jamil¹  Kiran Iqbal Masood²  Maheen Hassan²  Muniba Islam²  Alnoor Akber²  Zahra Hasan² 

[1] Department of Medicine, The Aga Khan University;Department of Pathology and Laboratory Medicine, The Aga Khan University;

关键词: Tuberculosis;    QuantiFERON-TB GOLD;    Co-morbids;    Interferon gamma release assay;    Pulmonary TB;    Extra-pulmonary TB;   

DOI  :  10.1186/s40794-020-0102-z

来源: DOAJ

【 摘 要 】

Abstract Introduction There were 10 million new cases of tuberculosis (TB) in 2017. To eliminate TB, it is necessary to diagnose active TB and latent tuberculosis infection (LTBI). Diagnosis of paucibacillary disease and in extrapulmonary TB (EPTB) remains challenging; low mycobacterial load can be missed by microbiological or molecular based confirmation; EPTB, can be misdiagnosed due to absence of site specific specimens for testing. Interferon gamma release assays (IGRA) use T cell-based Interferon-gamma (IFN-γ) to identify infection with M. tuberculosis (MTB) but cannot discriminate between active and LTBI. We investigated how IGRA was being used in a high burden low resource setting. Methods We conducted a retrospective review of 149 consecutive cases received for QuantiFERON-TB Gold In-Tube Assay (QFT-GIT) testing in routine clinical service. Results Fifty-six cases were QFT-GIT positive and 93 were QFT-GIT negative. Thirty-six per cent of QFT-GIT tested cases had active TB. Of QFT-GIT positive cases, 59% patients had active TB; 10 with pulmonary and 23 with extra-pulmonary TB. The remaining 41% QFT-positive cases were LTBI. Of the QFT-GIT negative cases, 22% had active TB. Co-morbid conditions were present in 37% of QFT-GIT positive and 60% of QFT-GIT negative cases. Conclusions Our study shows that IGRA is being used as an adjunct test for active TB in this population. It highlights the complexity of interpreting QFT-GIT results particularly for QFT-GIT negative cases when ruling out MTB infection.

【 授权许可】

Unknown