First rapid laboratory test for West Nile virus wins FDA approval.(90%-99% Sensitivity)

The first rapid laboratory test for diagnosis of West Nile virus will help physicians quickly rule out other conditions when patients present with suspicious symptoms.

The Food and Drug Administration on July 8 approved the test after a fast-track review of clinical trials of the West Nile Virus IgM Capture ELISA, manufactured in Brisbane, Australia, by PanBio Ltd.

By identifying IgM antibodies in patients' sera, the test makes it possible to make a presumptive diagnosis of West Nile virus within a few days of the onset of illness, with 90%-99% sensitivity. The test will be available to any accredited clinical laboratory, so samples will no longer have to be sent to large reference labs or state public health labs.

But the test lacks specificity in distinguishing West Nile virus from similar viruses, so confirmatory tests must be done on any patient with a positive result, as specified in current Centers for Disease Control and Prevention diagnostic guidelines, FDA officials stressed.

The approval nearly coincided with an announcement regarding the first confirmed human case of West Nile virus in 2003. A 70-year-old South Carolina outdoorsman who was bitten by mosquitoes while fishing in a lake was diagnosed with the infection, officials with the CDC confirmed in early July.

The patient from Oconee County, which borders Georgia, presented for care on May 29 with flulike symptoms and was diagnosed with meningoencephalitis. The man has since recovered, said Dr. Mike Bunning, an epidemiologist with the CDC's division of vector-borne infectious diseases, and Thom Berry, a spokesman for the South Carolina Department of Health and Environmental Control.

By July 9, West Nile virus activity had been reported in 31 states in the Northeast, Midwest, and South, with cases ...