Background: The use of expanded criteria kidneys has plateaued, possibly due to inadequate pathologic evaluation or lack of a universal grading system. We examined pre-transplant biopsy reports from various organ procurement organizations and compared them to reports from our transplant pathologists to determine which parameters were consistently reported.

Methods: Consecutive biopsy reports were collected prospectively from January to July 2014 at our institution and scored using the Maryland Aggregate Pathology Index (MAPI). The United Network for Organ Sharing (UNOS) database was queried for donor demographics, medical history, and outside biopsy reports. Parameters compared between biopsy reports were glomerulosclerosis, interstitial fibrosis, arteriosclerosis, arteriolar hyalinosis, and tubular atrophy.

Results: 78 kidneys from 51 donors were analyzed. These included 34 Expanded Criteria Donors, 12 Standard Criteria Donors, and 5 Donors after Cardiac Death. There were 26 males and 25 females. Median age was 59 years. Average Kidney Donor Profile Index was 82.7. On our institution's biopsies, the median MAPI score was 8, with a score of <8 considered suitable for transplantation, and 8-13 considered suitable with modified immunosuppression protocols. All Maryland and outside biopsies reported percent glomerulosclerosis. Interstitial fibrosis was scored in all 78 Maryland reports and in 75 outside reports. The other parameters were inconsistently reported by outside pathologists: arterial sclerosis in 62 vs. 76 (p=0.0007), arteriolar hyalinosis in 31 vs. 78, presence or absence of ATN in 18 vs. 78, diabetic changes in 4 vs. 78, and fibrin thrombi in 23 vs. 78 (all p<0.0001). Maryland reports did not comment on tubular atrophy in any reports, vs. 12 comments by outside pathologists (p=0.0003). The MAPI score also comments on periglomerular fibrosis and cortical scarring, which were not reported in outside biopsies.

Conclusions: This prospective analysis reveals severe inconsistencies in the reporting of potentially critical elements of donor kidney biopsies. Glomerulosclerosis and interstitial fibrosis were the only two parameters consistently reported, even though studies have shown that these alone are not sufficient for evaluating the quality of donor kidneys. Development of a standardized biopsy reporting system is warranted, and may reduce discard of kidneys that could otherwise be transplanted.

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