The traditional criteria for the diagnosis of allergic fungal sinusitis include chronic rhinosinusitis, "allergic mucin" (mucus containing clusters of eosinophils), and detection of fungi by means of histological examination or culture. In 1999, a group of Mayo Clinic researchers, with a novel method of mucus collection and fungal culturing technique, were able to find fungi in 96% of patients with chronic rhinosinusitis