The US Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) to another diagnostic test for the 2009 H1N1 influenza virus.

The EUA has been granted to Focus Diagnostics for a real-time reverse transcription polymerase chain reaction (RT-PCR) diagnostic test, for use in the detection of the 2009 H1N1 influenza virus in patients with symptoms of respiratory infection.

The FDA has the ability to issue an EUA, which grants temporary approval for the use of unapproved medical products or unapproved uses of approved medical products during an emergency. The authorisation will end when the declaration of emergency is terminated or when the FDA revokes the authorisation.

The EUA for the Focus Diagnostics Influenza H1N1 RT-PCR diagnostic test is the third diagnostic test authorised under an EUA by the FDA since the H1N1 influenza virus was declared a public health emergency on 26 April 2009.

Under the EUA Focus Diagnostics will distribute the test to laboratories certified under the Clinical Laboratory Improvement Amendments to run the complex laboratory test, which requires specialised equipment.

FDA Centre for Devices and Radiological Health director Daniel G Schultz said: “this authorisation will contribute to the nation’s capacity for accurate testing for the 2009 H1N1 influenza virus.”

The test amplifies the viral genetic material obtained from swabs of the nose or throat, or from nasal discharges.

A positive result indicates that the patient is infected with the 2009 H1N1 influenza virus. The test, however, does not indicate the stage of infection and a negative result does not prove that there is no influenza virus infection.