Interpretation of Laboratory Values in a 30-Year-Old Female
Overall Assessment
These laboratory values are entirely normal and do not indicate kidney disease. The low serum creatinine (0.55 mg/dL) and elevated eGFR (126 mL/min/1.73 m²) reflect normal physiologic variation in a young woman with relatively low muscle mass, while the urine albumin-to-creatinine ratio of 5.3 mg/g is well within the normal range 1, 2.
Individual Parameter Interpretation
Serum Creatinine (0.55 mg/dL)
This value is normal and expected for a young female. Serum creatinine reflects not only renal excretion but also creatinine generation from muscle mass, dietary intake, and metabolism 3.
Women typically have lower serum creatinine values than men due to lower muscle mass, and values between 0.5-1.0 mg/dL are completely normal in this demographic 4, 2.
Serum creatinine alone should never be used to assess kidney function because it is affected by multiple factors beyond GFR, including muscle mass, age, sex, and dietary protein intake 1, 2.
Estimated GFR (126 mL/min/1.73 m²)
This elevated eGFR is an artifact of the low serum creatinine and does not represent hyperfiltration or kidney disease. eGFR formulas (MDRD and CKD-EPI) are unreliable at the extremes of muscle mass and systematically overestimate true GFR when serum creatinine is very low 1, 2.
The MDRD equation has known limitations, including systematic underestimation of measured GFR at higher values and lack of validation in healthy young adults 1.
eGFR values above 120 mL/min/1.73 m² in young women with low muscle mass are common and do not indicate pathology 4, 2.
Urine Albumin-to-Creatinine Ratio (5.3 mg/g)
Calculating the ratio: 6.6 mg/dL albumin ÷ 124.8 mg/dL creatinine × 100 = 5.3 mg/g, which is well below the threshold for albuminuria.
Normal albuminuria is defined as <30 mg/g on spot urine albumin-to-creatinine ratio 2, 5.
This value of 5.3 mg/g indicates no glomerular damage and confirms the absence of kidney disease 2.
BMI 26.2 kg/m²
This BMI places the patient in the overweight category (25.0-29.9 kg/m²).
While elevated BMI is a long-term predictor of reduced eGFR and increased albuminuria in men, the association is weaker in women 6.
At this level and age, BMI 26.2 does not significantly impact current kidney function but represents a modifiable risk factor for future kidney disease if it increases further 6, 7.
Clinical Significance and Recommendations
No Evidence of Kidney Disease
Chronic kidney disease requires evidence of kidney damage OR reduced GFR (<60 mL/min/1.73 m²) persisting for at least 3 months 2.
This patient has neither criterion: the eGFR is elevated (not reduced), and the urine albumin is normal (not elevated) 1, 2.
Important Caveats
The elevated eGFR should not be misinterpreted as hyperfiltration syndrome (which occurs in early diabetes or obesity-related kidney disease), as the urine albumin is completely normal and there are no other indicators of kidney stress 4, 2.
eGFR calculations assume steady-state conditions and are only validated for monitoring kidney function over months to years, not for single time-point assessments in healthy individuals 4, 2.
Follow-Up Recommendations
No specific kidney-related follow-up is needed based on these results alone 1, 2.
Routine health maintenance should include blood pressure monitoring (target <130/80 mmHg) and weight management to prevent future kidney disease risk 6, 7.
If there are other clinical concerns (diabetes, hypertension, family history of kidney disease), repeat assessment of urine albumin and serum creatinine in 1-2 years would be reasonable, but this is not indicated by the current laboratory values 5.