Diagnostic Significance of Urinary Biomarkers in Congenital Upper Urinary Tract Obstruction

Background:
Congenital obstructive uropathy represents an important contributor to morbidity in the paediatric population and may result in long-term renal impairment if not recognized and managed appropriately. Despite advances in imaging and functional assessment, an accepted gold standard for accurately diagnosing renal obstruction in children is still lacking. Conventional diagnostic modalities often have limitations in predicting the severity of obstruction and the extent of renal damage. In this context, the non-invasive assessment of urinary biomarkers has gained increasing attention, as it offers a safe, repeatable, and child-friendly approach for evaluating renal injury. Assessment of biomarker concentrations in urine collected through normal voiding holds promise for improving early diagnosis, guiding clinical decision-making, and monitoring disease progression or recovery following intervention. The purpose of this review is to examine recent research on the usefulness of urinary biomarkers for diagnosing obstructive uropathy and assessing patient outcomes during follow-up in children.
Methods: Recent studies highlight several biomarkers such as NGAL, KIM-1, MCP-1, PAI-1, and L-FABP, which indicate early tubular injury, inflammation, and fibrosis. These biomarkers were reviewed for their diagnostic accuracy, correlation with obstruction severity, and their value in monitoring response after surgical interventions like valve fulguration or pyeloplasty.
Results: Biomarkers such as NGAL and KIM-1 rise significantly in early tubular injury, even when serum creatinine is normal. MCP-1 and PAI-1 reflect inflammation and future fibrosis, helping predict long-term renal outcomes. L-FABP increases in renal hypoxia seen in severe obstruction. Many studies show that biomarker levels decrease after surgical relief of obstruction, indicating kidney recovery. Biomarkers also help differentiate true obstruction from non-obstructive hydronephrosis.
Conclusion: Biomarkers provide a non-invasive, sensitive, and early method to detect renal injury in congenital urinary obstruction. Their use can improve diagnosis, guide treatment decisions, and predict long-term renal outcomes better than traditional tests. Incorporating biomarkers into routine evaluation may help prevent chronic kidney disease in affected children.