What is the estimated glomerular filtration rate (eGFR) for a 36-year-old male with impaired renal function, as indicated by a creatinine level of 115.61 umol/L?

eGFR Calculation for 36-Year-Old Male with Creatinine 115.61 µmol/L

For a 36-year-old male with serum creatinine of 115.61 µmol/L (1.31 mg/dL), the estimated GFR using the CKD-EPI equation is approximately 68-72 mL/min/1.73 m², which represents normal kidney function and does not meet criteria for chronic kidney disease. 1

Conversion and Calculation Method

• First, convert the creatinine from µmol/L to mg/dL: 115.61 µmol/L ÷ 88.4 = 1.31 mg/dL 1

• The National Kidney Foundation and American Society of Nephrology recommend using the CKD-EPI equation refit without race variable for GFR estimation, as it provides superior accuracy compared to the MDRD equation, particularly at GFR values >60 mL/min/1.73 m² 1

• Using the MDRD equation as an alternative: eGFR = 186 × (1.31)^-1.154 × (36)^-0.203 = approximately 65-68 mL/min/1.73 m² 1

Clinical Interpretation

• This eGFR of approximately 68-72 mL/min/1.73 m² does not meet criteria for chronic kidney disease (CKD), which is defined as eGFR <60 mL/min/1.73 m² or presence of albuminuria ≥30 mg/g creatinine 1

• Normal GFR is approximately 130 mL/min/1.73 m² for men, with a mean decline of 0.75 mL/min/year starting in the third or fourth decade, so this value is within expected range for a 36-year-old male 1

• A GFR below 60 mL/min/1.73 m² is associated with increased prevalence of CKD complications and cardiovascular risk, but this patient is above that threshold 2, 1

Important Clinical Caveats

• Serum creatinine alone should never be used to assess kidney function because it is affected by muscle mass, creatinine generation, tubular secretion, and extrarenal excretion independent of GFR 1, 3

• Factors that can elevate creatinine independently of kidney damage include recent exercise, infection, fever, marked hyperglycemia, hypertension, dietary creatine/creatinine intake from meat consumption, and creatine supplementation 1, 3

• eGFR calculations assume steady-state conditions and are invalid when creatinine is acutely elevated from non-renal causes 3

• Extremes of muscle mass, obesity, or amputees may have inaccurate GFR estimates, and measured GFR using exogenous filtration markers should be considered in these populations 1

• Clinical laboratories should report eGFR rounded to the nearest whole number using units of mL/min/1.73 m², and creatinine should be measured using enzymatic methods where possible, which is more specific than the Jaffe method 1