Autoantibodies to glomerular basement membranes (GBM) are highly specific and sensitive markers for Goodpasture’s syndrome. The prevalence of GBM antibodies in patients with lung involvement amounts to 80-90%, in patients without lung involvement to 60%. GBM antibodies have shown to be crucial for an early diagnosis of the disease. Since the clinical progression of the disease correlates with antibody concentration, with high-titers indicating an unfavourable prognosis, ELISA-based quantification of GBM autoantibodies enables a monitoring of the course of disease. A regular,quantitative determination of the autoantibody titer supports the monitoring of the therapy success, since the titer correlates with the disease activity.