FDA clears test for 12 specific respiratory viruses

Jan 4 2008

The U.S. Food and Drug Administration has cleared for marketing a test that simultaneously detects and identifies 12 specific respiratory viruses.

The test, called the xTAG Respiratory Viral Panel, is the first test for the detection and differentiation of influenza A subtypes H1 and H3. Influenza A is the most severe form of influenza for humans, and has been the cause of major epidemics. The new panel is also the first test for human metapneumovirus (hMPV), newly identified in 2001.

The xTAG Respiratory Viral Panel amplifies viral genetic material found in secretions taken from the back of the throat in patients with possible respiratory tract infections. In the test, specific beads, or microspheres, bind to the amplified viral genetic material. The beads are then sorted so that the specific virus can be identified.

The xTAG panel is the first FDA-cleared test for infectious respiratory disease viruses that uses a multiplex platform, allowing several tests to be processed using the same sample.

"Nucleic acid tests such as the xTAG Respiratory Viral Panel utilize small amounts of genetic material, and then replicate it many times," said Daniel G. Schultz, M.D., director of FDA's Center for Devices and Radiological Health.

"This speeds up the usual process of detecting and identifying respiratory viruses, which can take up to a week," said Schultz. "And, because this multiplex viral panel tests for 12 viruses at once, it uses less of a patient's test specimen."

Other viruses identified by the xTAG Respiratory Viral Panel:

• influenza B - one of three types of human influenza, less severe than influenza A
• respiratory syncytial virus subtype A and B – both are leading causes of infant pneumonia and bronchiolitis (an infection of the airways leading to the lungs) and often contribute to the development of long-term pulmonary disease
• parainfluenza 1, 2 and 3 – all are leading factors in the croup and the common cold
• rhinovirus – the most common viral infective agent in humans and a cause of the common cold
• adenovirus – a cause of respiratory tract infections often similar to strep throat or tonsilitis

While the test is faster than conventional tests, it is specific to the dozen viruses listed and should be used with other diagnostics such as patient data, bacterial or viral cultures and X-rays. Positive results do not rule out other infection or co-infection and the virus detected may not be the specific cause of the disease or patient symptoms.

The xTAG Respiratory Viral Panel is manufactured by Toronto-based Luminex Molecular Diagnostics.