Aspergillus IgG antibody is a laboratory test which is performed on the blood. This test is ordered by the doctor when they suspect an infection on the patient’s body caused by the fungus Aspergillus. Aspergillus fumigatus is considered as one of the ingenious agents of invasive lung disease and hypersensitivity pneumonitis along with pneumonitis or cavitation and allergic bronchopulmonary disease. The development of allergic bronchopulmonary and HP disease caused by Aspergillus fumigatus is assisted by an immune response to Aspergillus fumigatus antigens with the production of IgG antibody. Antibodies are immunoglobulin proteins which are made by the immune system in response to harmful substances called antigens. An antigen is a substance that is recognized as a threat by the body.