Study: QuantiFERON-TB Gold test yields fewer false positives

A recent study conducted by Connecticut and Georgia researchers found that the QuantiFERON-TB Gold assay led to fewer false positives for tuberculosis than the tuberculin skin test.

Tuberculosis screening typically involves testing for latent tuberculosis infection with the tuberculin skin test. After receiving a positive diagnosis, patients are offered therapy to treat the disease. The QFT-G test is designed to more specifically test for Mycobacterium tuberculosis infection.

The QFT-G test is meant to yield fewer false positive tuberculosis test results, a phenomenon that is known to occur with the TST among people vaccinated with the bacillus Calmette-Guerin TB vaccine.

The researchers used the QFT-G test with adults who were referred to a pulmonary clinic after receiving a positive TST result. Among 100 adults who were vaccinated with BCG and had a positive TST result, only 30 had a positive QFT-G result.

The study also found that patients from high-incidence countries were 8.2 times more likely to have a positive QFT-G result when compared to patients from low incidence countries.

The researchers determined that the QFT-G assay could more effectively identify patients that would benefit most from LTBI treatment following a positive TST result.

The study was completed by researchers from the University of Connecticut Medical Center, the Centers for Disease Control and Prevention, the Connecticut Department of Public Health, and the St. Francis Hospital and Medical Center. The research was published in the Journal of Infection and Public Health.