Qiagen has announced the US launch of QuantiFERON-TB Gold Plus (QFT-Plus), the fourth generation of its leading blood test for tuberculosis (TB) infection. QFT-Plus kits will be available on October 9, 2017 for diagnostic use following US Food and Drug Administration approval in June.

QFT-Plus advances the science of TB testing with innovative antigens that measure the cell-mediated immune response to tuberculosis infection from both CD4+ and CD8+ T cells – providing a broader assessment of TB infection. CD8+ T cells have been shown to play an important role in
Mycobacterium tuberculosis immunity.  

QFT-Plus builds on the foundation of QuantiFERON-TB Gold (QFT), the third generation of Qiagen’s world-leading interferon gamma release assay (IGRA). The new QFT-Plus test includes the following new features: Optimized CD8 T cell responses — Facilitates research on patient risk stratification of latent TB infections developing into active disease. Published evidence underlines the future potential of CD8+ T cells for distinguishing active from latent TB, discerning recent vs. old infections, detecting TB in certain populations such as HIV co-infection and young children, as well as assessing one's response to TB treatment. No other test is optimized for both CD4 and CD8 T cell responses.  

Expanded blood collection options — Collection and transport flexibility that enables customers to take control of the TB testing workflow with several blood collection options. QFT-Plus offers a new standard single-tube blood collection option that allows larger volume labs or remotely collected blood samples to be processed up to 53 hours after venipuncture for flexible transport to the lab. The existing "assay in collection tube" design for immediate stimulation of the blood sample continues to provide a direct draw option with the identical transport times as the previous QuantiFERON 3rd generation assay.

High sensitivity and specificity — QFT-Plus has a specificity of >97% and a sensitivity of >94%, producing more accurate results than the century-old tuberculin skin test (TST).

“QuantiFERON-TB Gold Plus sets a new benchmark in TB testing with the addition of specific CD8+ T cell stimulating antigens. Many clinicians have already realized the patient-centered aspects of a single visit to get a result and accuracy of laboratory testing over the tuberculin skin test. The proprietary CD4+/CD8+ T cell technology of QFT-Plus has the potential to provide important insights for high-risk patients such as contacts exposed to active TB or HIV-positive persons while maintaining high specificity,” said Dr. Masae Kawamura, Senior Director, TB Medical and Scientific Affairs, at Qiagen. “In the United States, test accuracy has never been more important as the country aggressively fights to end tuberculosis through recent policy-driven expansion of targeted testing and preventive treatment. It is currently estimated that 93% of the TB disease in the US comes from the 13 million-person reservoir of latent TB infection.”

The US introduction of QFT-Plus follows adoption in more than 75 countries across Europe, the Middle East, Africa, Asia and Latin America, where nearly two million of the new tests have already been used. More than ten peer-reviewed publications to date have supported the performance of QFT-Plus, and studies underway in 22 countries involve more than 30,000 patients. QFT-Plus is the only IGRA test on the pathway to evaluation by the World Health Organization (WHO) for its global campaign to eradicate TB.

Tuberculosis is a contagious bacterial infection spread primarily by coughing of patients with the active pulmonary form of the disease. In 2015, WHO estimates, there were 10.4 million new cases of active TB worldwide and 1.8 million deaths from TB. In latent tuberculosis infection (LTBI), the bacterium infects a person but produces no symptoms unless it progresses to the active disease. On a global basis, approximately one out of three people are estimated to have latent TB infection, and about 5-10% of those individuals, if untreated, will progress to active tuberculosis at some point. Screening of high-risk individuals and treatment for LTBI play an important role in tuberculosis control efforts in the US and many European countries, as well as in other developed and emerging markets around the world.