What is the clinical significance of an estimated glomerular filtration rate of 72 mL/min/1.73 m² in a 42‑year‑old female and what follow‑up is recommended?

Clinical Significance of eGFR 72 mL/min/1.73 m² in a 42-Year-Old Female

An eGFR of 72 mL/min/1.73 m² in a 42-year-old woman does NOT constitute chronic kidney disease unless evidence of kidney damage is present. 1

Understanding the GFR Category

• This patient falls into KDIGO category G2 (eGFR 60–89 mL/min/1.73 m²), which represents "mildly decreased GFR" 2, 1
• G2 alone is insufficient for CKD diagnosis—you must document kidney damage persisting >3 months 2, 1
• Normal GFR in young adults is approximately 125 mL/min/1.73 m², so 72 represents roughly 58% of expected normal function 2
• However, healthy adults commonly have eGFR values >63.5 mL/min/1.73 m² without disease 3

Required Next Steps to Determine CKD Status

You must actively search for evidence of kidney damage through:

1. Measure urine albumin-to-creatinine ratio (UACR) 1

   • A1 (<30 mg/g) = normal to mildly increased 1
   • A2 (30–300 mg/g) = moderately increased, confirms CKD 1
   • A3 (>300 mg/g) = severely increased, confirms CKD 1

2. Repeat serum creatinine and eGFR within 3 months to verify chronicity 1

3. Review for other damage markers 1:

   • Kidney imaging abnormalities (cysts, scarring, asymmetry)
   • Urine sediment abnormalities (hematuria, cellular casts)
   • Blood/urine composition abnormalities (electrolyte disorders from tubular dysfunction)
   • Pathological findings if biopsy performed

4. Consider cystatin C measurement if eGFR approaches 60 or clinical uncertainty exists, as approximately two-thirds of borderline cases are reclassified when cystatin C is added 1

Clinical Interpretation

• If UACR is normal (<30 mg/g) and no other damage markers exist: This is NOT CKD; the eGFR of 72 likely represents normal variation for this individual 1, 3
• If UACR ≥30 mg/g or other damage is present: CKD is confirmed and should be classified as G2A2 (or A3) with identified cause 2, 1

Risk Stratification

• An eGFR of 72 without albuminuria carries low risk for adverse kidney and cardiovascular outcomes 2
• Population-based data show eGFR values below the 25th percentile for age/sex are associated with increased mortality and kidney failure risk 4
• At age 42, median population eGFR is substantially higher than 72, placing this patient potentially below the 25th percentile and warranting albuminuria assessment 4

Follow-Up Recommendations

If no kidney damage is found:

• No CKD diagnosis warranted 1
• Repeat eGFR annually if risk factors present (diabetes, hypertension, family history) 5
• No nephrology referral needed 1

If CKD is confirmed (damage present):

• Annual monitoring of eGFR and UACR 1
• Increase monitoring to quarterly if treatment targets not met 1
• Implement kidney-protective interventions: RAS inhibition if albuminuria present, blood pressure optimization (<120 mmHg systolic if tolerated), SGLT2 inhibitor if diabetic, lifestyle modification 5
• Nephrology referral is NOT indicated at eGFR 72 unless progressive decline, increasing albuminuria, or uncertain etiology develops 1

Common Pitfalls to Avoid

• Do not diagnose CKD based on a single eGFR value in the G2 range without confirming damage 1
• Do not assume age-related decline—at 42 years, this eGFR warrants investigation 2, 4
• Do not skip albuminuria testing—it is mandatory to complete the diagnostic evaluation 1
• Do not refer to nephrology prematurely—referral thresholds are eGFR <30, progressive decline, or diagnostic uncertainty 1