Evaluation of Nephrolithiasis and Its Risk Factors in Living Kidney Donor Candidates

CT imaging detects Randall's plaques as false positives; true stone prevalence in donor candidates is 2–8%, half the general population rate.

Journal: Current Opinion in Organ Transplantation | Published: 2026-03-17 | Type: Narrative Review | PMID: 41846320 Authors: Stuart M. Flechner (Cleveland Clinic Lerner College of Medicine, Glickman Urology and Kidney Institute) Funding/COI: Not listed for either

Summary

Kidney stone disease affects roughly 10% of the U.S. general population but only 2–8% of living kidney donor candidates — likely reflecting the healthier baseline of people who volunteer. Modern CT imaging complicates evaluation by flagging Randall's plaques (calcifications in renal papillae) as apparent stones, which they are not. When metabolic risk factors are absent and the retained kidney is stone-free, this review concludes donation outcomes are acceptable.

Claims

• U.S. kidney stone prevalence: ~10% in the general population
• Prevalence among donor candidates: reported at 2–8%
• Current CT resolution detects calcifications ≤1–2 mm, raising detection sensitivity but also false-positive rates via Randall's plaques
• Recurrent stone disease in donors and stone-related complications in recipients are described as "uncommon, limited to a few percentage of patients" — no precise figure given
• Donation is supported by current data when: (1) no metabolic stone risk factors, and (2) retained kidney is stone-free

Study Quality

This is a single-author narrative review with no described search strategy, inclusion criteria, or quality assessment of cited studies. That makes it an expert opinion piece dressed as a review. There is no systematic synthesis — the author selects supporting evidence to frame a clinical conclusion rather than evaluating the totality of evidence. The journal, Current Opinion in Organ Transplantation, publishes invited expert perspective pieces by design, so this format is expected — but it should not be mistaken for a systematic review or meta-analysis.

No primary data are presented. Quantitative claims (the "few percentage" of stone complications) lack cited sources within the abstract. Without knowing which studies underpin the 2–8% figure or the outcomes claim, independent verification is impossible from this summary alone.

Red Flags

• No systematic search method described — selection bias in cited literature is likely
• "A few percentage of patients" for donor complication rate is vague and uncited in the abstract
• No funding or COI disclosed; Cleveland Clinic has an active transplant program with institutional interest in broad donor eligibility criteria
• Single-author review limits peer challenge of conclusions
• Randall's plaque vs. active stone disease distinction is clinically important but the practical decision threshold is not defined here

Strengths

• Addresses a real clinical gap: stone history is common and donor evaluation protocols vary
• Highlights a genuine imaging artifact problem (Randall's plaques) that affects donor disqualification decisions
• Published in a specialist journal read by transplant surgeons making these exact calls
• The core conclusion — that metabolic workup, not just imaging, should drive eligibility — is a defensible and practically useful framing

Verdict

This is a thought-leader opinion piece, not primary evidence. The central practical point — that incidental CT calcifications shouldn't automatically disqualify donors, and that metabolic risk stratification matters — is plausible and clinically relevant, but the paper provides no new data to back it up. Useful as an orientation to the debate; useless as a standalone evidence source. Transplant programs making policy on stone-positive donors need the underlying studies, not this summary of them.