anti-glomerular basement membrane antibody anti-glomerular basement membrane antibody anti-glomerular basement membrane antibody (anti-gbm ab) is an antibody which is found in goodpasture's syndrome but not found in microscopic polyangiitis. some sources consider "anti-gbm disease" and "goodpasture disease" to be synonymous terms describing histological presentation, reserving the term "goodpasture syndrome" for clinical presentation.