No single test has both good sensitivity and specificity for the diagnosis of ABPA—a definitive diagnosis depends on 8 parameters which include the following: asthma or CF; immediate Aspergillus skin prick test positivity, IgE levels > 1000 IU/mL, positive A. fumigatus specific IgE (no value specified or studied), Aspergillus precipitins (or IgG) detectable, eosinophil count > 1,000 cells/uL, transient pulmonary radiographic opacities, (central) bronchiectasis and high attenuation mucus [4–6]. The gene discussed is IGHE; the disease is cystic fibrosis.