Normal Creatinine and eGFR Values for a 61-Year-Old Woman
Yes, a creatinine level of 0.68 mg/dL and an eGFR of 99 mL/min/1.73 m² are completely normal for a 61-year-old woman and indicate excellent kidney function.
Understanding Normal Reference Ranges
For women with normal renal function, serum creatinine typically ranges from 0.6 to 1.0 mg/dL (55–90 µmol/L), making 0.68 mg/dL well within the expected normal range 1.
- Age-specific reference data shows that for women aged 55-65 years, the upper reference limit for creatinine is approximately 1.0 mg/dL 1.
- Research examining healthy populations aged 25-65 years found reference limits for serum creatinine in women ranging from 0.93-1.00 mg/dL at the 95th percentile 2.
Interpreting the eGFR Value
An eGFR of 99 mL/min/1.73 m² places this patient in Stage 1 kidney function (≥90 mL/min/1.73 m²), which represents normal or increased GFR 1.
- Normal GFR in young adults is approximately 120-130 mL/min/1.73 m², and it naturally declines with age 3.
- Approximately 17% of persons older than 60 years have an eGFR less than 60 mL/min/1.73 m², making an eGFR of 99 quite favorable for this age group 3.
- Reference limits for eGFR in women aged 55-65 years range from approximately 58-84 mL/min depending on the calculation method used 2.
Clinical Significance
This combination of values indicates no evidence of chronic kidney disease and represents preserved renal function for her age 1.
- The patient's kidney function is better than expected for her age, as age-related GFR decline is common but not universal 3.
- No metabolic monitoring, medication dose adjustments, or nephrology referral would be indicated with these values 1.
Important Caveats
Serum creatinine can be influenced by muscle mass, and lower values may reflect reduced muscle mass rather than superior kidney function 1, 3.
- In elderly individuals, serum creatinine concentration does not always accurately reflect GFR due to age-related decline in muscle mass that reduces creatinine generation 3.
- A creatinine of 0.68 mg/dL could reflect either excellent kidney function or lower muscle mass typical of older women 1.
- If there are concerns about accuracy, cystatin C-based eGFR measurement could provide additional information, though it is not necessary with these normal values 4.