Luminex Corp has cleared labeling updates for the company’s xTAG® Respiratory Viral Panel (RVP) to include data about the performance of the test in humans infected with the pandemic strain of influenza A, 2009 influenza A/H1N1, which is sometimes referred to as “swine flu.”

The test’s labeling has been updated to include information from two new studies that demonstrate that xTAG RVP can be an effective aid in the detection of 2009 Influenza A/HIN1, but cannot identify the hemagglutinin gene of the 2009 Influenza A/H1N1 in clinical specimens.
 
“The studies now referenced in the xTAG RVP package insert demonstrate that the test can help determine if a patient is carrying a typical, seasonal respiratory virus or an unsubtypeable flu A virus,” said Patrick J. Balthrop, president and chief executive officer of Luminex. “The xTAG RVP test can be a critical first line of defense in virus surveillance and in separating patients with more common respiratory infections from novel cases.”
 
xTAG RVP was first cleared by the FDA in January 2008. It is the only commercially available test that can simultaneously detect 12 respiratory viruses and subtypes, including influenza A with subtyping, at the DNA/RNA level. xTAG RVP was designed to detect the matrix gene that is shared across several influenza A strains, including 2009 influenza A/H1N1. In contrast, it does not detect the hemagglutinin gene of the 2009 Influenza A/H1N1 strain; whereas, it detects the hemagglutinin gene of seasonal strains of H1N1 and H3N2. This design enables xTAG RVP to provide 3 types of results for patients infected with influenza A: 1) influenza A-H1; 2) influenza A-H3; 3) influenza A-unsubtypeable.
 
The xTAG RVP package insert has been updated to reference two recent publications of studies led by Dr. Christine Ginocchio, Director of Microbiology, Virology and Molecular Diagnostics at North Shore-LIJ Health System Laboratories:
 
"Evaluation of Multiple Test Methods for the Detection of the Novel 2009 Influenza A (H1N1) during the New York City Outbreak.”i This study evaluated the performance of a variety of diagnostic tests, including xTAG RVP, for 2009 Influenza A/H1N1 surveillance. A total of 2,715 patient samples were tested by xTAG RVP and 1,265 of these were positive for influenza A. Of the 1,265, 1,108 were influenza A-unsubtypeable, 151 were influenza A-H3, and 6 were influenza A-H1. Of the 1,108 flu A unsubtypeable samples tested by the x TAG RVP, all were confirmed to be the 2009 Influenza A/H1N1 with the CDC rRT-PCR assay for the 2009 Influenza A/H1N1.
 
“Likelihood that an unsubtypeable Influenza A result in the Luminex xTAG Respiratory Virus Panel is indicative of novel A/H1N1 (swine-like) influenza.”ii In this study, which was carried out during the 2009 Influenza A/H1N1 (swine flu) outbreak in New York, 1,382 patient samples were initially tested with a variety of methods including rapid antigen tests, direct immunofluorescence, and rapid virus culture. Samples that tested positive for Influenza A with any of these methods, or derived from patients with a high potential to be infected with the 2009 Influenza A/H1N1 strain, were further tested with xTAG RVP. A total of 201 samples were identified as Flu A positive by xTAG RVP: 2 influenza A-H1, 58 influenza A-H3, 141 influenza A-unsubtypeable. Frozen residual portions were available for 101 of the 141 unsubtypeable samples tested on xTAG RVP and were forwarded to the Laboratory of Viral Diseases (Albany, NY) for further testing with the CDC rRT-PCR assay for 2009 Influenza A/H1N1 (swine flu). A total of 99 of the 101 specimens tested with the CDC assay were identified as positive for 2009 A/H1N1. (CT<37).

Source: Luminex