Role of on-site microscopic evaluation of kidney biopsy for adequacy and allocation of glomeruli: comparison of renal biopsies with and without on-site microscopic evaluation.

Evaluation of kidney core biopsies ideally begins with on-site microscopic examination for adequacy and allocation of tissue for light microscopy (LM), immunofluorescence (IF) and electron microscopy (EM). However, some renal biopsies are not microscopically evaluated by a pathologist at the time of procedure, and are allocated without on-site evaluation. This study compares the actual outcome of these two techniques. We reviewed the reports of patients who underwent kidney biopsy for medical causes in the past two years. Eighty-eight biopsies had on-site microscopic evaluation by pathologists, and 70 biopsies did not undergo on-site evaluation. For biopsies without on-site evaluation, no glomeruli were seen in 5 (7.14%) cases for LM, 11 (15.71%) cases for IF and 6 (8.57%) cases for EM. In cases with on-site evaluation, the absence of glomeruli was identified in 1 (1.13%) case for LM, 3 (3.4%) for IF and 3 (3.4%) for EM. The biopsies with on-site microscopic evaluation had 5.68% of the cases considered as inadequate, while 22% of biopsies without on-site evaluation were considered inadequate. The biopsies with on-site evaluation tended to have more glomeruli obtained during the procedure (p < 0.0005). Without on-site evaluation, the likelihood of getting an inadequate specimen compared to on-site evaluation is nearly four times greater.