MELBOURNE, Australia, July 25, 2011 /PRNewswire/ — A new policy
recommendation released on 20 July by the World Health Organization
(WHO) warns against the use of serological (blood) tests to
diagnose active tuberculosis (TB). Serological tests measure
antibodies to TB in serum and are different to QuantiFERON, which
measures responses of white blood cells to TB specific proteins.
Active tuberculosis occurs when the TB organism has overcome the
body’s immune defences and proliferates to cause clinical symptoms.
According to WHO, TB takes one life every 17 seconds
globally.(1) People with active disease often shed live TB bacteria
and infect others. A person who is infected with the bacteria that
causes TB, but who shows no symptoms and is not sick with the
disease, is said to have latent TB infection (LTBI).(2) People with
LTBI are at risk of developing active TB, particularly if their
immune system becomes depressed.(2)
QFT is intended as an aid to the diagnosis of TB infection, both
active and latent, and does not discriminate between the two
conditions. Cellestis Limited, manufacturer of QuantiFERON®-TB
Gold (QFT), has become aware that some media reports have caused
confusion around the WHO announcement. The press release from WHO
clearly notes that it refers to serological (antibody-based) blood
tests for active TB, and their comments do not apply to
Interferon-Gamma Release Assays (IGRAs) for diagnosing latent TB.
This has been confirmed by direct correspondence by WHO to
Cellestis.
“QuantiFERON-TB was developed in response to the poor quality of
previous tests such as those referred by WHO. We thoroughly agree
with the comments of WHO regarding serological tests for active
TB,” said Dr Jim Rothel, Chief Scientific Officer of Cellestis. “It
is imperative to recognize that TB is still one of the world’s
deadliest diseases. We are confident that QFT has the ability to
help reduce the future healthcare burden of TB, and
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