At the fixation process of kidney biopsies different fixatives are used and this may cause different pictures on histological slides in this study, all consecutive renal needle biopsies were separated into two cores and one core has been fixed in 4% formalin and theother in Bouin' solution. Paraffin sections were prepared and routinely stained. Staining quality of hematoxylin eosin, periodic acid Schiff, methenamine silver and Masson's trichrome stains and glomerular size were evaluated.

Visceral and parietal membranes of glomeruli were drawn using Zeiss Vision (KS 400 ver 1.2) image analysis software. Area, perimeter, and feret calculations were done by the system. Three-hundred and one glomeruli were evaluated. Perimeters of the parietal membranes were significantly higher İn the formalin-fixed group (p<0.0001), but visceral membranes were not (p>0,05). The quality of the special stains were similar between the groups. On hematoxylin eosin sections the observers were apparently aware of the differences and choose the samples fixed wİth their favored fixative.

As a result, it has been demonstrated that the type of the fixatives used affect the morphology of the glomeruli. Since that influence of the fixative may cause misdiagnosis, it has to be taken into account during diagnosis.