In 103 subjects with asymptomatic isolated haematuria (persisting for more than 6 months in the absence of proteinuria, bacteriuria, impaired haemocoagulation or urological disease) renal biopsy was performed. The mean age of the patients was 25.2 years, range 14-58 years. In 94% glomerular changes were detected--most frequently minimal glomerular lesions (67%) and proliferative mesangial glomerulonephritis (15%). Focal segmental proliferative glomerulonephritis was rare (4%). Immunofluorescent examination revealed IgA nephropathy in 40% (all cases of diffuse and focally segmental proliferative glomerulonephritis and one quarter of minimal glomerular lesions). Changes of tubules and interstitium were recorded in 26%, with the exception of one patient they were always associated with glomerular affection. From the investigation ensues that the predominating cause of isolated asymptomatic haematuria, not clarified by non-invasive examination, is usually not serious and is an affection frequently associated with tubulointerstitial changes. As many as 40% of isolated cases of haematuria may be the manifestation of IgA nephropathy. The deposition of IgA is more frequently associated with a more advanced grade of glomerular affection. Indication of diagnostic renal biopsy in isolated haematuria remains individual.

Keywords: Adolescent; Adult; Aged; Biopsy, Needle; Female; Glomerulonephritis /complications/; Hematuria /etiology/; Humans; Kidney /pathology/; Male; Middle Aged