Tuberculin skin test and interferon-γ release assay in the detection of latent tuberculosis infection among Polish health care workers

INTRODUCTION For many years, Poland has had a mandatory vaccination program against tuberculosis, which recommended repeated vaccinations from birth to adulthood. Therefore, the clinical value of the tuberculin skin test (TST) in diagnosing latent tuberculosis infection (LTBI) in Poland remains unclear. 
OBJECTIVES We conducted a study on the usefulness of the TST and QuantiFERON®-TB test (QFT) for the evaluation of the prevalence and risk factors of L TBI among Polish health care workers.
PATIENTS AND METHODS The study group consisted of the Polish health care workers. TST and QFT were performed in each participant. The usefulness of TST and QFT was tested in relation to occupational risk factors.
RESULTS A total of 305 participants were included. A positive TST result was observed in 149 cases (48.9%) and a positive QFT result was observed only in 27 cases (8.9%). In the subgroup that declared contact with tuberculosis (n = 44), positive QFT and TST results were found in 20.5% and 63.3% cases, respectively. Past contact with tuberculosis was the only significant variable associated with a positive TST result. Independent variables associated with positive QFT results were older age, lower education level, longer period of work in health care, and previous contact with tuberculosis.
CONCLUSIONS The QFT has a higher diagnostic value than the TST in the assessment of LTBI in Polish health care workers.