Clinical Utility and Impact of Phosphatidylethanol (PEth) Testing in Patients Pursuing Kidney Transplantation

Phosphatidylethanol (PEth) is a whole blood biomarker that detects alcohol use within the prior 28 days with excellent sensitivity and specificity. Although PEth is increasingly utilized in the screening process for solid-organ transplants and the clinical utility has been well defined in liver transplant candidates, PEth's utility in kidney transplantation is less well-defined.

We conducted a retrospective chart review of all patients evaluated for kidney transplantation who underwent PEth testing as part of their pretransplant evaluation between June 1, 2020, and June 30, 2024, across 3 tertiary referral centers. Extracted data included demographics, dialysis and transplant status, etiology of renal disease, psychiatric and substance use comorbidities, and psychosocial assessment scores. For patients with a positive PEth, we additionally reviewed patient-reported alcohol use, concurrent urine ethyl glucuronide results, and the influence of PEth on clinical decision-making, including changes to psychosocial scoring, substance use disorder diagnoses or treatment recommendations, and decisions on transplant listing status.

A total of 2472 patients (mean age = 56.8 years; 62.6% male; 66.3% White) received a PEth test as part of their transplant evaluation across the 3 campuses. Overall, 228 patients (9.4%) had at least one positive PEth test, with most values (81%) corresponding to moderate alcohol use (20-199 ng/mL). Among PEth-positive patients, 73.9% were diagnosed with a comorbid alcohol use disorder after a diagnostic exam from a mental health specialist. When ordered concurrently, PEth and urine ethyl glucuronide were discordant in 80% of cases. In nearly half of positive cases (46.5%), PEth identified a discrepancy from the patient's reported use pattern. PEth influenced clinical decision-making in 70.2% of positive cases, most commonly affecting listing status and substance use disorder treatment recommendations.

PEth testing enhanced the detection of alcohol use in kidney transplant candidates, identifying cases missed by urine ethyl glucuronide and self-report, and revealing discrepancies that frequently influenced clinical decision-making. The high prevalence of comorbid alcohol use disorder among PEth-positive patients suggests under recognition of at-risk alcohol use in this population. Routine PEth screening may enhance alcohol detection, guide targeted interventions, inform decision on listing status, and optimize kidney transplant outcomes.