Recurrent haematuria: role of renal biopsy and investigative morbidity.

The usefulness of renal biopsy in investigating unexplained haematuria was assessed by a study of 33 adults referred consecutively with this syndrome. Unequivocal abnormalities were seen on light microscopy or immunofluorescence in 31 of the 33 specimens of renal tissue examined. In 18 patients deposits of IgA were present in the mesangium. Loin pain occurred in only two of the 18 patients with mesangial IgA deposits, compared with 11 of the 15 patients without these deposits. Seven of the nine women in this series had had loin pain compared with only six of the 24 men. Thus a woman with loin pain and haematuria was not likely to have mesangial IgA nephropathy but this was found in 14 of the 18 men with unexplained painless haematuria. Failure to appreciate the role of renal biopsy in the investigation of unexplained haematuria may result in unnecessary radiology, considerable morbidity, and even in unjustified nephrectomy.