Clinical Utility and Performance of Urinary L-FABP as a Potentially Suitable Biomarker for Early Detection of Contrast-Induced AKI among Adult Filipino In-Patients Undergoing Coronary Angiography

Background: Contrast-induced AKI (CI-AKI) is now considered the third most common cause of AKI in hospitalized patients and is recognized as a frequent complication of percutaneous cardiovascular procedures. One significant barrier to improving clinical outcomes in patients with AKI is the delayed administration of potentially beneficial therapies. This delay is compounded by the unreliability of serum creatinine as a marker of GFR in acutely ill patients. Urinary levels of L-FABP have been shown to increase earlier than serum creatinine in patients who develop AKI and is particularly linked with tubular dysfunction. This biomarker could be valuable for assessing a patient’s risk, and for the early diagnosis of CI-AKI. Methods: This analytic prospective cohort study was conducted to determine diagnostic utility of urinary L-FABP in the early detection of CI-AKI among adult Filipino in-patients who underwent coronary angiography from December 2023 to April 2024. Baseline and 4-6 hour post-procedure urinary L-FABP levels were measured using point-of-care kits and compared between patients who developed CI-AKI (diagnosed using KDIGO criteria) and those who did not develop the disease. Results: The final analysis included 86 patients, 3 of whom were diagnosed with CI-AKI during the study period. ROC analysis showed that baseline urinary L-FABP exhibited 100% sensitivity and 73.49% specificity at a cut-off value of 2.71 ng/ml, while the 4-6 hour urinary L-FABP had 100% sensitivity and 98.8% specificity at a cut-off value of 10.99 ng/ml. The AUC for the baseline urinary L-FABP was 0.89 representing a good test, and 1.0 for the 4-6 hour urinary L-FABP indicating an excellent test in CI-AKI diagnosis. Conclusion: This study demonstrates that urinary L-FABP could serve as a clinically useful predictive biomarker to detect CI-AKI onset even before contrast media exposure. This biomarker, which has high sensitivity and good negative predictive value in the detection rate of AKI, may enable and improve timely initiation of preventive strategies and potentially beneficial therapies for CI-AKI.