What Is Kidney Function (eGFR) and What Does It Say About Your Kidney Health?

Your kidneys work around the clock to keep your body healthy. They filter waste products from the blood, remove excess fluids, regulate electrolyte levels, support blood pressure control, and help maintain overall balance within the body. Because kidney disease often develops silently, monitoring kidney function is an important part of preventive healthcare.

One of the most commonly used measures of kidney health is eGFR, which stands for Estimated Glomerular Filtration Rate. This value helps healthcare professionals estimate how effectively the kidneys are filtering waste from the bloodstream.

The glomeruli are tiny filtering units located inside the kidneys. Healthy kidneys contain millions of these microscopic filters that remove waste while keeping important substances in the body. The eGFR measurement estimates how much blood passes through these filters each minute.

An eGFR score is usually calculated using blood creatinine levels along with factors such as age and sex. Creatinine is a waste product generated by normal muscle activity. Healthy kidneys remove creatinine efficiently, while reduced kidney function may cause creatinine levels to rise.

Because kidney disease often develops gradually, many people experience no symptoms during the early stages. This is why eGFR testing is valuable. It can help identify kidney problems long before noticeable symptoms appear.

In general, an eGFR above 90 is considered normal for many healthy adults when no other signs of kidney damage are present. Scores below this range may require further evaluation depending on age, medical history, and additional test results.

An eGFR between 60 and 89 may indicate mildly reduced kidney function, particularly if other signs of kidney damage are present. Many individuals remain healthy within this range, but regular monitoring may be recommended.

An eGFR below 60 that persists for several months may suggest chronic kidney disease. The lower the eGFR score becomes, the more severely kidney function may be affected.