Are wedge biopsies of cadaveric kidneys obtained at procurement reliable?

Background. Single wedge biopsy of cadaveric kidneys from donors older than 55 is currently the standard method of evaluating their viability for tran splantation, The degree of glomerulosclerosis presently determines whether a kidney can be transplanted, but most biopsies sample only the subcapsular region and may not accurately represent the true renal architecture. Our s tudy evaluated the accuracy of transplant suitability determinations based upon the single wedge biopsy of cadaveric kidneys. Methods. We took kidneys that were refused by UNOS centers on the basis of biopsy results, examined their histology in detail, and reviewed donor medi cal histories. Sections were taken from the upper, lower, and mid-portion o f each kidney and stained with the periodic acid Schiff stain. Percentage a nd location of glomerulosclerosis and other relevant pathology were then de termined in each section. We compared our findings with the results of the original wedge biopsies obtained at the time of procurement. Results. Nine kidneys were obtained and examined, The wedge biopsies at the time of procurement showed glomerulosclerosis ranging from 8 to 36% (media n 17%). The multiple kidney sections we analyzed showed fewer sclerosed glo meruli, ranging from 3 to 15% (median 7%, P<0.001), with most of the sclero sed glomeruli identified located in the immediate subcapsular region (P<0.0 01). Conclusions. Wedge biopsies of donor kidneys can overestimate the total amo unt of glomerulosclerosis, apparently because of a predominance of sclerosi s in the kidney's subcapsular region, the area predominantly sampled by the usual wedge biopsy. These inappropriately high estimates of glomeruloscler osis can result in refusal of kidneys that might be suitable for transplant ation.