Evaluation of Novel Biomarkers of Acute Kidney Injury in Critically Ill Patients Admitted to Intensive Care Units in Abuja, North Central Nigeria

Serum creatinine and urine output criteria for acute kidney injury detection lack sensitivity for early tubular damage, creating an urgent need for novel biomarkers that enable earlier therapeutic intervention in critically ill patients. This study evaluated the diagnostic performance of novel AKI biomarkers in critically ill patients at the National Hospital Abuja, Federal Capital Territory. A prospective observational study was conducted among 120 patients admitted to the intensive care unit. Urine and serum samples collected at admission and at 24 hours were tested for NGAL, KIM-1, cystatin C, and IL-18 alongside conventional serum creatinine. AKI was classified by Kidney Disease Improving Global Outcomes criteria. Twenty-four-hour urine NGAL demonstrated AUC of 0.92 for AKI diagnosis preceding creatinine rise by a mean of 18 hours. Serum cystatin C showed AUC of 0.89 and outperformed creatinine in patients with reduced muscle mass and those on corticosteroids. KIM-1 was superior for detecting tubular injury in sepsis-associated AKI. Combining NGAL with KIM-1 improved sensitivity to 93.4%. Among conventional markers, urine output criteria alone missed 26.4% of AKI cases confirmed by novel biomarkers. NGAL levels at 24 hours independently predicted 30-day renal outcome and ICU mortality. The study establishes the superior early diagnostic value of NGAL and cystatin C over serum creatinine for AKI in Nigerian intensive care patients and recommends feasibility studies for implementing point-of-care NGAL testing in Abuja tertiary hospitals. Keywords: acute kidney injury, NGAL, cystatin C, biomarkers, intensive care unit