The estimated Glomerular Filtration Rate (eGFR) is a measurement that provides insight into how well your kidneys are functioning. Kidneys work as filters, removing waste products and excess water from your blood to produce urine. The eGFR specifically gauges the rate at which these filters, called glomeruli, clean your blood each minute. This calculation helps healthcare providers determine the overall health of your kidneys.
What Your eGFR 104 Result Means
An eGFR of 104 is considered an excellent result, indicating robust and healthy kidney function. For most adults, a normal eGFR is typically 90 or higher, placing a value of 104 well within this healthy range. This number reflects that your kidneys are efficiently filtering waste from your bloodstream.
While a single eGFR reading offers a snapshot, a consistent eGFR of 104 signifies sustained good kidney health. This suggests your kidneys are handling their workload without signs of impairment.
How eGFR is Determined and What Other Values Indicate
The eGFR is not a direct measurement but an estimated number derived from a simple blood test, primarily measuring creatinine levels. Creatinine is a waste product generated from the normal breakdown of muscle tissue and dietary protein. Healthy kidneys efficiently remove creatinine from the blood, but if kidney function declines, creatinine can build up.
Beyond creatinine, the eGFR calculation also incorporates several individual factors, including your age, sex, and body type (such as height and weight). These factors are included because they influence the normal levels of creatinine in the blood; for instance, individuals with more muscle mass typically have higher baseline creatinine levels. Some calculations may also use cystatin C, another protein, especially if creatinine results are unclear.
It is worth noting that eGFR naturally decreases with age, even in individuals without kidney disease. For example, the average eGFR for adults aged 20-29 is around 116, while for those 70 and above, it averages about 75. This gradual decline is a normal part of the aging process, reflecting structural changes in the kidneys over time.
When eGFR values fall below the normal range, they can indicate various stages of kidney impairment. An eGFR between 60-89 might suggest early-stage kidney damage, especially if other signs of kidney issues, like protein in the urine, are present. If an eGFR remains below 60 for three months or longer, it may point to chronic kidney disease (CKD).
Lower eGFR numbers, such as those between 30-59, indicate moderate kidney function loss, while values below 15 suggest kidney failure, potentially requiring dialysis or a kidney transplant. Monitoring eGFR over time, along with other tests like urine albumin-to-creatinine ratio (uACR), is important for detecting changes in kidney health and guiding any necessary interventions.