The role of kidney biopsy to determine donation from prospective kidney donors with asymptomatic urinary abnormalities

Background: There are no definite guidelines about donation among prospective donors with asymptomatic urinary abnormalities. We evaluated the pathology of prospective kidney donors with asymptomatic urinary abnormalities and assessed the clinical outcomes of their organs. Methods: We reviewed the medical records of 15 prospective kidney donors who underwent kidney biopsy. We evaluated the role of kidney biopsy in terms of graft function, protocol biopsy, and follow-up biopsy. We further assessed the clinical outcomes of donors and recipients. Results: Thin basement membrane nephropathy (TBMN) is the most common cause of the persistent microscopic hematuria (n = 7; 50%), followed by nonspecific findings (n = 4; 29%), IgA nephropathy (n = 2; 14%), and focal segmental glomerulosclerosis (n = 1; 7%). Of the 14 candidate donors with persistent microscopic hematuria, 9 were accepted as kidney donors: 5 with TBMN, 3 with mild mesangiopathy, and 1 with nonspecific interstitial changes. The function of the 9 grafts was relatively stable (mean serum creatinine level 2.38 mg/dL) over a mean follow-up of 57 months. Graft failure that developed in 2 grafts was not associated with biopsy findings: acute rejection and patient death with a functioning graft. Interestingly, basement membrane thickness in 2 allografts from donors with TBMN appeared normal by electron microscopy follow-up biopsy; the allografts did not show hematuria. Moreover, the clinical outcomes of donors were favorable (mean serum creatinine 0.94 ± 0.32 mg/dL) during the mean follow-up period of 34.7 ± 42.5 months. We did not observe new-onset hypertension or proteinuria in donors. Conclusions: Kidney biopsy in prospective kidney donors with urinary abnormalities is a safe and effective diagnostic procedure to stratify candidates. Therefore, kidney biopsy should be actively performed to improve the prognosis of both donors and recipients.