Emerging Biomarkers in Kidney Function Assessment: From Conventional Tests to Precision Diagnostics

Kidney diseases represent a significant global health challenge, particularly chronic kidney disease (CKD) and acute kidney injury (AKI), which contribute to high morbidity and mortality worldwide. Early detection and accurate assessment of kidney function are crucial for preventing disease progression and improving patient outcomes. Traditionally, kidney function has been evaluated using biomarkers such as serum creatinine, blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and albuminuria. While these markers are widely used in clinical practice, they have important limitations, including low sensitivity for early kidney injury and susceptibility to non-renal factors such as muscle mass, diet, age, and medications. Consequently, kidney damage may progress significantly before abnormalities are detected through conventional testing. Recent advances in molecular biology, proteomics, metabolomics, and systems medicine have facilitated the discovery of emerging biomarkers that may improve the early detection and monitoring of kidney dysfunction. Biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin C, tissue inhibitor of metalloproteinase-2 (TIMP-2), insulin-like growth factor binding protein-7 (IGFBP7), and soluble urokinase plasminogen activator receptor (suPAR) have shown promise in detecting renal injury earlier and more accurately than conventional biomarkers. Many of these markers reflect specific biological pathways such as inflammation, tubular injury, oxidative stress, and cell-cycle arrest. The integration of these emerging biomarkers with advanced diagnostic technologies, including artificial intelligence (AI), multi-omics platforms, and point-of-care biosensors, has led to the development of precision diagnostics in nephrology. These technologies allow clinicians to identify early molecular changes associated with kidney injury and personalize treatment strategies accordingly. Studies indicate that biomarkers such as NGAL may rise within hours of renal injury, significantly earlier than changes in serum creatinine, highlighting their clinical value for early diagnosis. This paper reviews conventional kidney function tests, examines their limitations, and discusses emerging biomarkers transforming kidney disease diagnostics. It also explores the role of modern technologies in enabling precision medicine approaches for kidney disease management.