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IMMY register new lateral flow immunoassay (IgG & IgM) for Coccidioides (Valley Fever)

November 16 2017

Valley Fever, caused by the soil-borne fungus Coccidioides, causes flu-like illness and occasionally pneumonia or meningitis in arid parts of North, South and Central America, with a recovery period lasting weeks or even months. Its incidence has markedly increased in recent years, and extended into non-endemic areas, but existing serological diagnostics are labour-intensive and slow — generally taking between 3 and 7 days.

IMMY (Oklahoma, USA) have registered a new lateral flow device (CTA2003, sona™) with the FDA, which delivers a result in less than 30 minutes on the basis of detection of both IgG and IgM. The test involves diluting serum in the diluent provided by IMMY, then inserting an assay strip that is read like a pregnancy test after 20 minutes. 

The test has a high negative predictive value (100%; CI=91–100%), meaning that it can be used to reliably rule out Valley Fever in uninfected patients, thus avoiding unnecessary treatment with antifungals. A positive result reduces the time to antifungal treatment, but would generally be followed up with traditional serological testing as the positive predictive value was lower (77%; CI=63–87%).