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FDA clears DxNA’s valley fever test
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The molecular diagnostics company DxNA LLC recently announced that the FDA had cleared its test for the rapid detection of coccidioidomycosis, or valley fever.
According to the company, the GeneSTAT.MDx Coccidioides test, which works with the GeneSTAT System, is performed directly on patient specimens and can produce same-day results. Currently, definitive testing for Coccidioides fungus is performed by culture in biosafety level 3 laboratories, and it can take up to 3 weeks to get results.
DxNA said the test was developed based on intellectual property licensed from the Translational Genomics Research Institute (TGen) and Northern Arizona University. The FDA’s decision to clear the test was based on a multicenter study that compared it with standard testing. According to the company, the GeneSTAT.MDx Coccidioides test has a sensitivity of 100%, specificity of 99.6% and reproducibility of 100%.
David Engelthaler, PhD, associate professor and co-director of the pathogen and microbiome division at TGen North, told Infectious Disease News that patients with valley fever may visit a health care provider six or seven times before they are finally tested for the disease. Providers often mistake valley fever for a bacterial infection and prescribe antibiotics, he said, and when a fungal infection is suspected, current Coccidioides tests — culture or serologic assays — take a long time to produce results and may delay clinical decision-making.
“There is now a new tool available to acurately diagnose valley fever — one of the important causes of community-acquired pneumonia — where there hasn’t really been before,” he said. “It’s exciting that we can use the power of genomics to get the right DNA biomarkers that will essentially rule in Coccidioides, which is the fungal cause of valley fever, or rule it out.”
According to the CDC, Coccidioides fungal spores are spread through airborne dust in the southwestern United States and parts of Mexico and Central and South America. Cases also have been reported in Washington. Certain at-risk populations, including people with weakened immune systems such as those with HIV/AIDS or organ transplant patients, as well as pregnant women, people with diabetes and people who are black or Filipino, are at greater risk for developing severe forms of the disease. Valley fever is most common among those aged 60 years and older, the agency said.
Researchers estimated that the overall incidence of valley fever in states where the disease is endemic was 42.6 cases per 100,000 population in 2011.
Michael A. Saubolle, PhD, DABMM, FAAM, FIDSA, system medical director in the infectious diseases division at Laboratory Sciences of Arizona/Sonora Quest Laboratories, told Infectious Disease News that the number of coccidioidomycosis cases continues to rise, and there has been an upsurge in cases in California in 2017, underscoring the need for more diagnostic tools.
According to Saubolle, who is also a clinical associate professor of medicine at the University of Arizona College of Medicine, Phoenix, two molecular amplification methods for detecting Coccidioides using PCR have been published, but both lack FDA clearance and are not widely available to clinical laboratories.
“The recent FDA clearance of DxNA’s PCR-based GeneSTAT.MDx Coccidioides test now provides far greater opportunity for laboratories to add a rapid, very sensitive test to their diagnostic capabilities, thus providing faster and more accurate results,” Saubolle said. “The sensitivity of the new test is due to its use of a 106-bp target sequence repeated multiple times (approximately 60 times) per genome, thus lowering the limit of detection for extracted DNA of Coccidioides spp.”
Laboratory Sciences of Arizona/Sonora Quest Laboratories, Banner Health in Arizona, TriCore Reference Laboratories in New Mexico, and the University of Arizona in Tucson and Phoenix all participated in the clinical study to validate the test.
“Valley fever is such an important disease for those who live in or visit the Grand Canyon state or many other places in the southwest,” John N. Galgiani, MD, director of the University of Arizona’s Valley Fever Center for Excellence, said in the release. “We certainly can use better tools to help doctors diagnose it.”
Disclosures: TGen has liscened the GeneSTAT.MDx Coccidioides test to DxNA. Engelthaler reports owning stock in DxNA. Saubolle is system medical director in the infectious diseases division at Laboratory Sciences of Arizona/Sonora Quest Laboratories. Infectious Disease News was unable to confirm Galgiani’s relevant financial disclosures at the time of publication.
References:
CDC. Valley Fever (Coccidioidomycosis) Risk & Prevention. https://www.cdc.gov/fungal/diseases/coccidioidomycosis/risk-prevention.html. Accessed December 7, 2017.
CDC. MMWR Morb Mortal Wkly Rep. 2013;62:217-221.