Changes in Serum Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Their Relationship with Kidney Function in Different Stages of Chronic Kidney Disease

Background: The identification of reliable biomarkers for early diagnosis and monitoring of chronic kidney disease (CKD) progression is crucial for improving prognosis and treatment. Neutrophil gelatinase-associated lipocalin (NGAL) is a promising candidate, already validated as a marker for acute kidney injury. This study evaluates NGAL's potential as a biomarker for early diagnosis and monitoring the progression of CKD. Seventy-one patients at CKD stages G1–G4 according to the KDIGO criteria were divided into three groups: Group 1 (eGFR ≥90 mL/min/1.73m²), Group 2 (eGFR 45–89 mL/min/1.73m²), and Group 3 (eGFR 15–44 mL/min/1.73m²). Blood samples were collected and analyzed via standard biochemical and immunological techniques. Serum NGAL levels were measured using ELISA. Results: NGAL levels increased significantly with disease progression and strongly correlated with declining eGFR. Higher NGAL levels were linked to elevated serum creatinine and inflammatory markers, indicating progressive damage to the kidney tissue against the backdrop of persistent systemic inflammation. Conclusions: NGAL demonstrates considerable potential as a biomarker for early detection and monitoring of kidney damage progression. Its use in clinical practice could enrich the traditional methods of diagnosis and monitoring of patients with CKD.