IGHE and asthma: Of all the 61 studies that were cited to support these 25 recommendations, only one of the cited primary studies directly related to their corresponding guideline recommendations in ERS, deJong et al.36 The authors employed an appropriate study design to evaluate the diagnostic accuracy of spirometry, bronchodilator reversibility and serum IgE (in addition to other tests), in 111 consecutively sampled patients with suspected asthma.