Allergic bronchopulmonary aspergillosis: the hunt for a diagnostic serological marker in cystic fibrosis patients

The diagnosis of allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis patients remains challenging, mainly owing to overlapping symptoms of the underlying lung disease with clinical symptoms of ABPA. In addition, a varying mixture of diagnostic criteria, including clinical status, radiological findings and immunological measurements, has led to confusion and differing recommendations. In order to help simplify as well as standardize the diagnostic criteria for ABPA, different serological markers have been evaluated in the last 20 years and their usefulness has been assessed in many clinical studies. This review presents current diagnostic criteria of ABPA, with a special focus on serum markers supporting the diagnosis and explains why the hunt for a serological marker for ABPA is still ongoing.