However, although only to be positive in nHES, a case of PDGFRA-positive EGPA has been described (42); therefore, some authors believe that testing for PDGFRA mutation should be performed routinely in all cases with hypereosinophilia, regardless of clinical manifestation, suspected EGPA, or ANCA-status (170). This evidence concerns the gene PDGFRA and eosinophilic granulomatosis with polyangiitis.