Objectives: The presence of abnormally high levels of Aspergillus fumigatus-specific immunoglobulin (Ig) G antibodies can serve as a diagnostic criterion for severe conditions like allergic bronchopulmonary and chronic pulmonary aspergillosis. This study aimed to determine a reference range of A. fumigatus-specific IgG levels within a healthy adult Omani population.

Methods: This study took place during November 2015 at the Sultan Qaboos University Hospital, Muscat, Oman. The sera of 125 healthy Omani blood donors were tested for A. fumigatus-specific IgG levels using an automated fluorescence enzyme immunoassay.

Results: Initially, the data were not normally distributed; however, log transformation and the exclusion of four outliers resulted in an acceptable Gaussian distribution. The reference range was 2.0-68.7 mg_A/L at the 2.5^th and 97.5^th percentiles, respectively, with 90% confidence intervals of 2.0-3.0 mg_A/L and 48.0-76.0 mg_A/L, respectively.

Conclusion: The A. fumigatus-specific IgG reference range within a healthy adult Omani population was comparable to those reported in other populations.