Diagnostic Accuracy of Urinary Interleukin-18 versus Serum Creatinine for Early Identification of Sepsis-Associated Acute Kidney Injury

International Journal of Medicine and Medical Sciences | Vol. 16, No. 5, May 2026 | pp. 33–40

DOI: 10.46882/2026/IJMMS/160033

Original Research Article

Diagnostic Accuracy of Urinary Interleukin-18 versus Serum Creatinine for Early Identification of Sepsis-Associated Acute Kidney Injury

Charles O. Igwe¹, Rachel L. Sanon², Anthony D. Boateng¹*

¹Department of Anesthesiology and Intensive Care, Faculty of Clinical Sciences, College of Health Sciences, University of Abuja, Abuja, Nigeria.

²Department of Nephrology, Faculty of Health Sciences, Université de Ouagadougou, Ouagadougou, Burkina Faso.

Abstract:

Sepsis-associated acute kidney injury (SA-AKI) significantly drives mortality in intensive care settings, but traditional serum creatinine changes lag behind renal structural harm. This prospective cohort study evaluated the diagnostic accuracy of urinary Interleukin-18 (uIL-18) for early identification of AKI among critically ill septic patients. We evaluated 130 adult patients admitted to the intensive care unit (ICU) meeting the Sepsis-3 diagnostic criteria with normal baseline renal function. Urinary IL-18 concentrations were quantified via enzyme-linked immunosorbent assay (ELISA) at admission, 6, 12, and 24 hours, while serum creatinine was monitored daily for 7 days. AKI was graded according to the KDIGO classification criteria. Thirty patients developed confirmed SA-AKI (23.1%) within 48 hours of admission. In the AKI group, uIL-18 levels rose significantly from a baseline of 42.4 ± 6.8 pg/mL to 186.5 ± 24.2 pg/mL at 6 hours post-admission (p < 0.01), long before significant serum creatinine modifications were observable. Receiver Operating Characteristic (ROC) analysis showed that 6-hour uIL-18 at a cutoff value of 140 pg/mL had a sensitivity of 90.0%, a specificity of 85.0%, and an Area Under the Curve (AUC) of 0.92 (95% CI = 0.85–0.97). In contrast, 24-hour serum creatinine achieved an AUC of only 0.65. Urinary IL-18 serves as a highly sensitive and precise early diagnostic biomarker for inflammatory tubular cell injury during sepsis, permitting early clinical risk stratification and fluid balancing optimization before functional filtration failure becomes established.

Keywords: Sepsis, Acute Kidney Injury, Interleukin-18, Biomarkers, Intensive Care Unit, Diagnostic Accuracy

Manuscript Timeline: Received: February 14, 2026; Revised: March 22, 2026; Accepted: April 11, 2026; Published: May 15, 2026.

Citation: Igwe CO, Sanon RL, Boateng AD. Diagnostic Accuracy of Urinary Interleukin-18 versus Serum Creatinine for Early Identification of Sepsis-Associated Acute Kidney Injury. International Journal of Medicine and Medical Sciences, 2026, 16(5): 33–40. DOI: 10.46882/2026/IJMMS/160033

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