Abstract: FR-PO1144
Urine Metabolic Profiles and Donation Decisions Among Living Kidney Donor Candidates with Nephrolithiasis
Session Information
- Transplantation: Clinical - Transplant Access, Recipient Evaluation, Living Donors, Pregnancy, and More
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2002 Transplantation: Clinical
Authors
- Belasy, Ahmed Roshdy Mansour Ali, Mayo Foundation for Medical Education and Research, Phoenix, Arizona, United States
- Mohamed Ahmed, Mariam Bakr Elseddik, Mayo Foundation for Medical Education and Research, Phoenix, Arizona, United States
- van der Walt, Charles, Mayo Foundation for Medical Education and Research, Phoenix, Arizona, United States
- Buras, Matthew R., Mayo Foundation for Medical Education and Research, Phoenix, Arizona, United States
- Rule, Andrew D., Mayo Foundation for Medical Education and Research, Phoenix, Arizona, United States
- Keddis, Mira T., Mayo Foundation for Medical Education and Research, Phoenix, Arizona, United States
Background
Kidney donor candidates with nephrolithiasis undergo careful evaluation to minimize donor risk, yet standard predonation CT imaging frequently detects small asymptomatic stones of uncertain significance. In prior work, radiographic stone burden influenced donation denial and predicted later symptomatic stone events, but urine metabolic data were unavailable. Although 24-hour urine testing is recommended in donor candidates with stones, its influence on candidacy remains unclear.
Methods
We studied adult living kidney donor candidates with radiographic or prior symptomatic kidney stone disease evaluated at Mayo Clinic. Demographics, clinical stone risk factors, CT-based stone burden, and 24-hour urine metabolic profiles were abstracted. Candidates were compared by donation status. Urine parameters included volume, pH, calcium, oxalate, citrate, uric acid, sodium, phosphorus, sulfate, magnesium, and supersaturation indices.
Results
Among 593 donor candidates with kidney stone disease, 315 donated and 278 did not. Compared with donors, non-donors had higher BMI, blood pressure, and were more likely male. 60 (22%) non-donors vs 49 (16%) donors had symptomatic stone event prior to donor evaluation (p=0.07). Non-donors had greater stone burden, including more bilateral stones (35.6% vs. 27.1%, p=0.026), higher total stone count (p=0.02), and larger maximum stone diameter (p=0.005). Among non-donors, 84/277 (30.3%) were denied due to stones. A 24-hour urine metabolic evaluation was completed in 223/314 donors (71.0%) and 137/274 non-donors (50.0%; p<0.001). Urine pH, volume, oxalate, citrate, uric acid, sodium, sulfate, and magnesium were similar by donation status. Non-donors had higher urine calcium (230.1 vs. 196.7 mg/day, p=0.020), calcium oxalate supersaturation (p=0.003), hydroxyapatite supersaturation (p=0.005), and brushite supersaturation (p<0.001).
Conclusion
Among donor candidates with nephrolithiasis, urine metabolic testing identified higher urine calcium and calcium-based supersaturation among non-donors, but most urine parameters were similar among those who did and did not donate. These findings suggest that metabolic abnormalities, particularly modifiable findings such as hypercalciuria, should be interpreted in the context of stone burden rather than used in isolation to exclude otherwise suitable donor candidates.
Acknowledgment
Generative artificial intelligence (ChatGPT, OpenAI) was used to assist with language refinement and organization of the abstract. All study data, analyses, scientific interpretation, and conclusions were written and critically reviewed by the authors. The authors supervised the use of the tool, and take full responsibility for the integrity and content of the work.