GFR of 86 in a 27-Year-Old
A GFR of 86 mL/min/1.73 m² in a 27-year-old is below the expected normal range and warrants further evaluation to determine if this represents early kidney disease or measurement variability. 1
Understanding Normal GFR for This Age
- Normal GFR in young adults is approximately 120-130 mL/min/1.73 m², making a value of 86 mL/min/1.73 m² approximately 30-35% below expected for this age group 2, 1
- This level represents loss of approximately one-third of expected kidney function for a young adult 2
- A GFR of 85 mL/min/1.73 m² would be considered excellent kidney function for a 65-year-old but is unusually low for a 25-year-old and may justify exclusion as a kidney donor 2
Clinical Significance
- A GFR less than 90 mL/min/1.73 m² in a young adult falls below the threshold used for kidney donor acceptance, indicating this is not considered normal kidney function for this age 2
- While a GFR of 86 mL/min/1.73 m² does not meet criteria for chronic kidney disease (CKD) stage 3 (which requires GFR <60 mL/min/1.73 m²), it may represent CKD stage 2 (GFR 60-89 mL/min/1.73 m²) if kidney damage markers are present 2
- The definition of CKD requires either decreased GFR or kidney damage (such as proteinuria) persisting for 3 or more months 2
Recommended Evaluation
Confirm the GFR Measurement
- Do not rely on a single estimated GFR (eGFR) calculation - the confirmatory test should not be the same as the screening test 2
- Serum creatinine alone should not be used to assess kidney function, particularly given potential variability in muscle mass and creatinine generation 1
- Consider measuring creatinine clearance with a 24-hour urine collection or using an alternative eGFR equation to confirm the finding 2
Assess for Kidney Damage Markers
- Measure urine albumin-to-creatinine ratio (ACR) in a random urine specimen - persistent proteinuria is the principal marker of kidney damage 2
- An ACR greater than 30 mg/g is considered abnormal (sex-specific cutpoints: >17 mg/g in men, >25 mg/g in women) 2
- Examine urine sediment for abnormalities 2
- Consider imaging studies if indicated by clinical presentation 2
Identify Potential Causes
- Evaluate blood pressure - systolic hypertension is strongly associated with faster GFR decline 3
- Screen for diabetes - diabetic kidney disease can present with reduced GFR even in young adults 2
- Assess for cardiovascular disease risk factors 2
- Review medications that may affect kidney function 1
Common Pitfalls to Avoid
- Do not dismiss this finding as "normal aging" - the age-related decline in GFR typically begins after age 30-40 years, and this patient is only 27 years old 1, 4
- Do not assume a single eGFR value is definitive - confirm with repeat testing or alternative measurement methods 2
- Do not overlook the need to assess for proteinuria - kidney damage can be present even with GFR >60 mL/min/1.73 m² 2
Follow-Up Strategy
- Repeat GFR assessment in 3 months to determine if this represents persistent kidney dysfunction (required for CKD diagnosis) 2
- If confirmed low and/or proteinuria is present, refer to nephrology for comprehensive evaluation 2
- Monitor blood pressure closely and optimize control if elevated 3
- Adjust medication dosing if needed based on reduced kidney function 1