Biomarkers in Kidney Health: Enhancing Early Detection and Treatments

Emerging biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) have shown great potential in the early diagnosis of kidney injury. These biomarkers are extremely sensitive indicators of tubular injury, and they can detect renal damage at stages when conventional markers are still within normal ranges. While these novel biomarkers have high sensitivity and specificity, incorporating them into ordinary clinical practice raises several problems. Despite its potential, more study is needed to validate these biomarkers in large-scale, long-term clinical studies.

- Dr Ajay A Phadke

Doctors rely on assessing kidney function to diagnose and manage kidney disease. For years, medical professionals have used traditional indicators such as serum creatinine, blood urea nitrogen (BUN), and the calculated estimated glomerular filtration rate (eGFR) to check and track kidney health. These tests are widely accessible and useful for monitoring the gradual loss of kidney function. However, they have a significant limitation: they often fail to detect problems until substantial kidney damage has already occurred. This is particularly concerning in glomerular diseases, where early damage may go unnoticed until the kidneys are severely impaired.

For patients at high risk of kidney problems—such as those with diabetes, high blood pressure, or a family history of kidney disease—the urinary microalbumin-to-creatinine ratio has become an important tool. This measurement can detect early kidney damage, even when blood creatinine levels appear normal by identifying small increases in albumin excretion in the urine. Early detection allows doctors to begin treatment sooner, potentially slowing the progression of chronic kidney disease (CKD) and reducing the risk of cardiovascular complications.

Cystatin C, a low molecular weight protein produced by all nucleated cells, has also gained attention as a biomarker for kidney function that may be more accurate than creatinine. Unlike creatinine, cystatin C levels are less influenced by factors such as muscle mass, age, or diet. This makes it especially valuable in populations where serum creatinine may be unreliable, such as the elderly or individuals with low muscle mass. Despite its advantages, cystatin C has yet to become a routine part of clinical practice due to higher testing costs, variability in laboratory measurements, and the lack of standardised reference ranges.