What does an estimated glomerular filtration rate (eGFR) of 81 mL/min/1.73 m² indicate about my kidney function?

What an eGFR of 81 mL/min/1.73 m² Means for Your Kidneys

An eGFR of 81 mL/min/1.73 m² indicates mildly reduced kidney function (Stage G2) but is within the normal range for many adults, particularly those over age 40, and does not indicate kidney disease unless other markers of kidney damage are present. 1

Understanding Your eGFR Value

Normal Range Context

• Young adults typically have eGFR values of 100-130 mL/min/1.73 m² in men and 90-120 mL/min/1.73 m² in women. 1
• Your value of 81 mL/min/1.73 m² falls into the "mildly decreased" category (60-89 mL/min/1.73 m²) but may be completely normal depending on your age. 1
• Kidney function naturally declines after age 40, with progressive decreases in eGFR as part of normal aging. 1, 2

Age-Specific Interpretation

• In healthy 80-year-old individuals, the median eGFR is approximately 63-66 mL/min/1.73 m², with the 95th percentile around 81-84 mL/min/1.73 m². 2
• This means an eGFR of 81 mL/min/1.73 m² would be excellent for an older adult but slightly below optimal for a young adult. 2
• Reference intervals for healthy adults range from approximately 63.5-139.2 mL/min/1.73 m² depending on the equation used. 3

Does This Mean You Have Kidney Disease?

Critical Distinction

An eGFR above 60 mL/min/1.73 m² does NOT diagnose chronic kidney disease (CKD) unless other evidence of kidney damage is present. 1, 3

What Defines Kidney Disease at This Level

You would only have CKD Stage G2 if you have:

• Persistent albuminuria (protein in urine) documented on at least two occasions 3 months apart. 1
• Structural kidney abnormalities on imaging (such as polycystic kidneys, scarring, or masses). 1
• Biopsy-proven kidney disease. 1
• Other laboratory markers of kidney damage. 1

If No Other Abnormalities Are Present

• An isolated eGFR of 81 mL/min/1.73 m² without proteinuria or structural abnormalities likely represents normal kidney function for your age. 1
• CKD requires persistent abnormalities for at least 3 months, so a single measurement is insufficient for diagnosis. 1

Clinical Significance and Risk

Cardiovascular and Mortality Risk

• The lowest mortality risk occurs at eGFR 60-74.9 mL/min/1.73 m², with slightly increased risk at higher levels (eGFR 90-104.9 has hazard ratio 1.8 compared to referent). 4
• Your eGFR of 81 mL/min/1.73 m² falls in a range with minimal excess risk. 4
• The presence of proteinuria significantly amplifies risk at any eGFR level, including values above 90 mL/min/1.73 m². 4

Functional Capacity

• An eGFR of 81 mL/min/1.73 m² represents approximately 81% of the kidney function expected in a young adult with optimal kidney health. 5
• This level of function is more than adequate for normal metabolic needs and medication clearance. 1

What You Should Do

Immediate Actions

• Verify the result is accurate by ensuring the blood test was done in a stable health state (not during acute illness, dehydration, or immediately after surgery). 1
• Check for proteinuria by measuring urine albumin-to-creatinine ratio (UACR) to determine if kidney damage is present. 1
• Repeat eGFR in 3 months if this is your first measurement, as CKD diagnosis requires persistent abnormalities. 1

Ongoing Monitoring

• If no proteinuria or other kidney damage markers are present, annual eGFR monitoring is sufficient. 6
• Monitor blood pressure, as hypertension can both cause and result from kidney disease. 6
• Avoid nephrotoxic medications, particularly NSAIDs (ibuprofen, naproxen), which reduce kidney blood flow. 6

When to Worry

• Rapid decline in eGFR (>5 mL/min/1.73 m² per year) warrants nephrology referral. 6
• Development of proteinuria (UACR ≥30 mg/g) indicates kidney damage requiring further evaluation. 6
• eGFR dropping below 60 mL/min/1.73 m² on repeat testing defines CKD Stage 3a and requires more intensive monitoring. 5

Common Pitfalls to Avoid

Measurement Accuracy Issues

• Extremes of muscle mass (very muscular or very frail individuals) can make creatinine-based eGFR inaccurate. 1
• If your eGFR seems discordant with your clinical picture, request a cystatin C-based eGFR for confirmation. 6
• Serum creatinine alone should never be used to assess kidney function; always use calculated eGFR. 1

Overinterpretation

• Do not assume kidney disease based solely on an eGFR of 81 mL/min/1.73 m² without other evidence of kidney damage. 1, 3
• Normal values overlap with CKD Stage 1-2 values, so context (age, proteinuria, imaging) is essential. 3

Bottom Line

Your eGFR of 81 mL/min/1.73 m² most likely represents normal kidney function for your age, particularly if you are over 40 years old and have no proteinuria or other markers of kidney damage. 1, 2 This level of kidney function does not require treatment, medication adjustments, or dietary restrictions unless other abnormalities are identified. 1 Annual monitoring and avoidance of nephrotoxic medications are prudent. 6