Normal eGFR Values and Age-Related Decline
Yes, a healthy person can have an eGFR of 74 mL/min/1.73m², as this falls within the Stage 2 CKD range (60-89 mL/min/1.73m²) which represents a mild decrease in GFR that can be normal for certain age groups. 1
Understanding eGFR and Normal Ranges
The normal level of GFR varies according to age, sex, and body size:
- In young adults, normal GFR is approximately 107-130 mL/min/1.73m² 2, 3
- GFR typically remains stable until age 40, then begins to decline 3
- After age 40, there is a physiological decline of approximately 1 mL/min/1.73m²/year (or about 1.29% per year) 4
Age-Related eGFR Decline
The decline in eGFR with age is considered physiological:
- By age 65, median eGFR decreases to approximately 90 mL/min/1.73m² 5
- For adults over 70, mean eGFR may be around 59 mL/min/1.73m² 6
Interpreting an eGFR of 74
An eGFR of 74 mL/min/1.73m² falls within Stage 2 CKD classification (60-89 mL/min/1.73m²) 2, 1. However:
- This value may be entirely normal depending on the person's age
- For middle-aged or older adults, this represents normal kidney function
- For younger adults (<40 years), this may represent a mild reduction from expected values
Clinical Significance
While an eGFR of 74 mL/min/1.73m² is classified as Stage 2 CKD by definition, several important points should be considered:
- Without other markers of kidney damage (such as albuminuria), this value alone is not diagnostic of kidney disease 2
- The KDOQI guidelines emphasize that clinicians should not use serum creatinine or eGFR as the sole means to assess kidney function 1
- Age-related decline in GFR should not be dismissed as simply "normal aging" as it still predicts adverse outcomes and requires appropriate monitoring 1
Risk Assessment
The clinical significance of an eGFR of 74 depends on several factors:
- Age: More concerning in a 30-year-old than a 70-year-old
- Presence of albuminuria: Significantly increases risk even within the same GFR category 1
- Rate of decline: Rapid decline (>3% per year) is more concerning than stable values 7
- Other risk factors: Hypertension, diabetes, and cardiovascular disease increase the significance of mild GFR reductions 1
Monitoring Recommendations
For individuals with eGFR in the 60-89 mL/min/1.73m² range:
- Monitor eGFR and albuminuria every 6-12 months 1
- Assess for other markers of kidney damage (albuminuria, hematuria, structural abnormalities)
- Evaluate and manage cardiovascular risk factors
- Avoid nephrotoxic medications when possible
Common Pitfalls
- Over-diagnosis: Labeling someone with CKD based solely on a mildly reduced eGFR without other evidence of kidney damage
- Under-recognition: Failing to recognize that an eGFR of 74 in a young adult may represent significant reduction from expected values
- Ignoring trends: Not monitoring for progressive decline, which is more concerning than stable values
- Missing comorbidities: Failing to evaluate for conditions that may explain reduced eGFR
In conclusion, an eGFR of 74 mL/min/1.73m² can be entirely normal, especially in middle-aged or older adults, but should be interpreted in the context of age, other markers of kidney damage, and overall health status.