Aspergillus Galactomannan for Diagnosing Invasive Aspergillosis

A 67-year-old man with granulomatous polyangiitis treated with prednisone and azathioprine has a positive galactomannan enzyme immunoassay and fungal cultures positive for Aspergillus fumigatus in bronchoalveolar lavage fluid obtained for evaluation of dyspnea and a cavitary pulmonary nodule. How would you interpret the test results?