1. Reliability of GFR assessment in transplant patients. Many GFR estimating equations are in clinical use (creatinine, cystatin C, combined; CKD-EPI, FAS, EKFC), but none is accurate enough for individual decisions. Physicians and clinical laboratorians need to know when an estimate is sufficient and when measured GFR, such as iohexol clearance, is required.

2. Impact of laboratory results on living kidney donor eligibility. Guidelines ((KDIGO, OPTN, BTS, and Canadian KPD) set different renal function thresholds for living donor eligibility. The British and Canadian guidelines use age-adjusted thresholds. In our cohort of 1,210 living donor candidates, no eGFR equation reliably ruled out ineligible donors, but several performed well at ruling in acceptable donors. Age- and sex-specific thresholds improved eligibility classification across all equations.

3. Impact of heavy alcohol use on liver transplant decisions and outcomes. Alcohol-associated liver disease accounts for about 40% of the liver transplant waitlist. Phosphatidylethanol, now recommended by AASLD, objectively reflects alcohol use over the preceding 2-4 weeks. In our cohort, higher PEth levels were associated with lower transplant rates and more post-transplant liver complications.