A variety of diagnostic tests are available to detect the presence of influenza viruses in respiratory specimens. The most widely available tests are referred to as rapid influenza diagnostic tests (RIDT). These tests can be performed in a clinical setting, and results are typically provided within 30 minutes. However, these tests are not very sensitive (10-70 percent) for specific detection of 2009 H1N1 influenza, so a negative RIDT result does not rule out influenza virus infection. Furthermore, an RIDT is unable to distinguish between influenza A subtypes (i.e., 2009 H1N1 vs. seasonal H1 and H3 viruses).

 

According to the CDC, if rapid identification of 2009 H1N1 influenza virus infection is required, testing with a rRT-PCR assay specific for 2009 H1N1 influenza should be performed. Several rRT-PCR assays have been evaluated and authorized by the FDA under an emergency use authorization to diagnose 2009 H1N1 influenza virus infection. Genetic Assays, a Nashville-based molecular diagnostics laboratory that specializes in PCR-based infectious disease testing, recently added a 2009 H1N1 influenza rRT-PCR assay to its test menu. This FDA-authorized test is performed in accordance with the CDC protocol of realtime RTPCR for influenza A (H1N1), revised 30 April 2009.

 

In certain situations, influenza diagnostic testing of patients who are not severely ill may help inform decisions regarding clinical care, infection control, or management of close contacts. Testing specifically for 2009 H1N1 influenza may be important for patients with certain high-risk conditions, such as pregnancy, immunosuppression, heart disease, asthma, and diabetes. The CDC recommends that rRT-PCR tests be prioritized for hospitalized patients and immunocompromised persons with suspected influenza where RIDTs are negative. They should also be used to determine influenza A virus subtype in patients who have died from suspected or confirmed influenza A virus infection.

 

Genetic Assays performs another test cleared by the FDA as an effective aid in the detection of 2009 influenza A/H1N1 - the xTAG^® Respiratory Viral Panel from Luminex Corporation. Initially approved for marketing by the FDA in January 2008, the xTAG^® RVP uses multiplex PCR to detect and identify 12 different respiratory viruses and viral subtypes from a single patient sample. Its ability to detect the hemagglutinin gene of the seasonal strains of H1 and H3 is what enables the RVP to differentiate between common subtypes and the novel 2009 H1N1 strain.

 

"For the past 15 years, Genetic Assays has earned the reputation of improving patient care through the rapid diagnosis of disease and doing so as the best cost provider," said Mike A. Mammarelli, president and CEO of Genetic Assays, Inc. "With growing concerns about control of influenza virus infection, especially in facilities that specialize in critical care and treatment of high-risk patients, we believe that it is important to have this low cost H1N1 testing capability available in the Nashville market."