How is valley fever (coccidioidomycosis) diagnosed?
Accurate diagnosis of coccidioidomycosis is important because there are many diseases that have similar initial symptoms and may occur in areas of the world where coccidioidomycosis occurs; for example, Andes virus (caused by a hantavirus), arbovirus encephalitis (caused by six different viruses), Argentine hemorrhagic fever (an arenavirus infection caused by Junin virus), cryptococcosis (caused by Cryptococcus neoformans, a fungal species), and others. Fortunately, a confirmative diagnostic test is easily done by microscopic examination of sputum or a tissue biopsy that show characteristic fungal spherules and endospores of Coccidioides immitis or Coccidioides posadasii. These fungi can also be identified after they are cultured on fungal media (growth takes about five days). Additionally, there are several serum tests and a PCR test (to detect the genetic material of the fungus) that are available. High blood levels of IgG (an immunoglobulin) that react with the fungi can help determ
