The autologous serum skin test in a cohort of chronic idiopathic urticaria patients compared to respiratory allergy patients and healthy individuals.

Background: A positive autologous serum skin test (ASST) is considered to reflect the presence of anti-FceRI and/or anti-IgE autoantibodies that are capable of activating mast and basophil cell degranulation. The ASST is regarded as a reliable in vivo test in chronic idiopathic urticaria (CIU) patients, with diagnostic, therapeutic and prognostic implications. However, positive ASST results have also occasionally been demonstrated in patients with other diseases and in healthy subjects.