Analysis of QuantiFERON®-TB Gold Plus test results among patients with chronic inflammatory diseases and HIV patients.

Objective: Screening for latent tuberculosis (LTB) is necessary, especially for people living with human immunodeficiency virus (HIV) and people receiving anti-TNF therapy. Although there is no microbiological test accepted as the gold standard, interferon-gamma release assays (IGRAs) are suggested to be used by World Health Organization. We aimed to analyze QuantiFERON^®-TB Gold Plus test results in different patient groups with high reactivation risk.

Methods: Patients admitted to Marmara University Pendik Training and Research Hospital Microbiology Laboratory between August 2016 - March 2020 have been analyzed retrospectively. Patient demographic data was obtained from the records of the laboratory information management system. Blood samples have been studied as recommended by the manufacturer (QuantiFERON^®-TB Gold Plus, QIAGEN, Germany).

Results: We evaluated samples from 1506 patients, of whom with a chronic inflammatory disease (CID) in 1223 patients and HIV positivity among 283 patients. Mean age was 38.29±12.66 for HIV patients and 41.57±14.45 for chronic inflammatory disease patients. QFT test was positive in 319 (21.2%) of 1506 patients in total and in 43 (15.2%) of HIV patients and in 276 (22.6%) of CID patients. Indeterminate results were obtained in 1.7% (n=26) of the samples. Among patients with CID highest rate of QFT test positivity was detected among patients with psoriasis (27.8%), followed by patients with rheumatoid arthritis (21.8%) and ankylosing spondylitis (19.8%). Active tuberculosis was not developed in any of QFT-GIT-positive CID patients followed up in our hospital for the 4 years period.

Conclusion: QuantiFERON^®-TB Gold Plus test requires a short-term and one-time contact with the patient and it seems to be a suitable option for screening of patients who have a high risk of tuberculosis.