As an additional measure in the fight against Zika virus, the Food and Drug Administration (FDA) announced that it has made available a panel of human plasma samples to aid in the regulatory evaluation of serological tests to detect recent Zika virus infection.
“At the onset of the Zika virus outbreak, when little was known about the disease or how to diagnose it, the FDA worked quickly with manufacturers to encourage the development of diagnostic tests and ensure they were available using its Emergency Use Authorization authorities,” said FDA commissioner Scott Gottlieb, MD. “By providing manufacturers of these tests with standardized patient samples to use in properly validating these diagnostics, we will be able to better assess how well their tests perform. This is part of our effort to ultimately bring these tests through the FDA’s formal review process to better ensure their reliability, and to enable broader access to Zika diagnostic testing.”
There are two primary blood diagnostic tests: nucleic acid tests that identify infection by confirming the presence of a virus’ genetic material (RNA) and serological tests that identify proteins (antibodies) produced by the body's immune system when it detects harmful organisms, such as Zika virus, in the blood. Serological tests are especially important because there is often a small window when the virus’ genetic material is detectable. However, development of these types of tests has been particularly challenging because antibodies produced by the body to fight Zika virus are difficult to differentiate from antibodies produced to fight related viruses, such as dengue and West Nile viruses.
The FDA’s sample panel consists of plasma samples from anonymous individuals infected with Zika, West Nile, or dengue viruses. Although the panel is not for research purposes, diagnostic developers can use these samples to assess whether their tests can help distinguish recent Zika virus infection from infection with West Nile or dengue viruses. Using the same serological panel to evaluate different devices available under Emergency Use Authorization (EUA) will help public health professionals compare the performance of different Zika virus tests.
The FDA panel is available to developers who have interacted with the FDA through the pre-EUA process and have devices that are in the final stages of validation. To date, the FDA has granted EUAs to three serological tests for detection of recent Zika virus infection (in chronological order): Zika MAC-ELISA, ZIKV Detect IgM Capture ELISA, and LIAISON XL Zika Capture IgM Assay. Other developers interested in requesting a panel may contact the agency.
The panel was prepared using samples from Zika virus-infected individuals provided by Blood Systems Research Institute (BSRI) from a study supported by Contract No. HHSN268201100001I from the National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH). The content of this press release is solely the FDA’s responsibility and does not necessarily represent the official views of BSRI, the NHLBI, or the NIH. The samples from individuals infected with dengue and West Nile virus were obtained separately by the FDA.