Presepsin, age and kidney function: A temporally validated upper limit conditioned on estimated glomerular filtration rate

Presepsin is renally cleared but assessed against a fixed threshold. We examined age, kidney function and presepsin, and derived an estimated glomerular filtration rate (eGFR)-conditioned upper limit.

First adult presepsin results at a Korean tertiary hospital (2020-2026) were linked with same-day C-reactive protein (CRP) and creatinine (12,455 patients); eGFR was calculated with the European Kidney Function Consortium (EKFC) eq. (2021 CKD-EPI for sensitivity). In 6296 patients with CRP <1 mg/dL, the 97.5th percentile of presepsin was modeled on eGFR, age and sex by quantile regression and evaluated in a test set, by cross-validation and in 2026, with a creatinine-stability sensitivity analysis.

Per decade of age, presepsin was 1.086-fold higher after adjustment for CRP, sex and setting, 1.048-fold after adding creatinine and 0.997-fold after adding EKFC eGFR (1.011 with CKD-EPI). Among patient-days with CRP <1 mg/dL, 20.2% at eGFR ≥90 and 98.0% below 15 exceeded 500 pg/mL. Each halving of eGFR raised the limit 1.68-fold (95% CI 1.51-2.00). A limit derived before 2026 was exceeded by 1.7% of 2026 results (nominal 2.5%), and the whole-population limit by 2.2% of patients with stable kidney function. Among all patients with eGFR <30 mL/min/1.73 m², 500 pg/mL flagged 96.2% and the conditioned limit 14.4%.

Creatinine accounted for about half of the age association and eGFR, which contains age, for nearly all of it. The conditioned limit reduced eGFR-related variation in exceedance, but the 2026 rate was below 2.5%; diagnostic value for sepsis requires validation.