eGFR Calculation for 53-Year-Old Male with Creatinine 89 μmol/L
The estimated GFR for this patient is approximately 88 mL/min/1.73 m², calculated using the CKD-EPI equation, which indicates normal kidney function for his age. 1
Calculation Method
Use the CKD-EPI equation refit without race variable, as this is the current recommended standard for GFR estimation and provides superior accuracy compared to older formulas, particularly at GFR values >60 mL/min/1.73 m². 1
Step-by-Step Calculation:
Convert creatinine from μmol/L to mg/dL: 89 μmol/L ÷ 88.4 = 1.01 mg/dL 1
Apply the CKD-EPI equation for a 53-year-old male with serum creatinine 1.01 mg/dL, which yields an eGFR of approximately 88 mL/min/1.73 m² 1
Alternative calculation using MDRD equation (older but still validated): eGFR = 186 × (1.01)^-1.154 × (53)^-0.203 = approximately 85 mL/min/1.73 m² 1
Clinical Interpretation
This eGFR represents normal kidney function for a 53-year-old male, as 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. 1
An eGFR ≥60 mL/min/1.73 m² does not meet criteria for chronic kidney disease (CKD) 1
This patient's kidney function is appropriate for his age, as age-related decline would predict a GFR of approximately 90-100 mL/min/1.73 m² for a 53-year-old 1
No medication dose adjustments are required, as drug dosage adjustments for renally excreted medications are only considered when eGFR falls below 60 mL/min/1.73 m² 1
Important Clinical Caveats
Never use serum creatinine alone to assess kidney function, as it is affected by muscle mass, creatinine generation, tubular secretion, and extrarenal excretion independent of GFR. 1
Factors that can falsely elevate creatinine include recent exercise, infection, fever, marked hyperglycemia, or hypertension 1
Extremes of muscle mass, obesity, or amputees may have inaccurate GFR estimates, and measured GFR using exogenous filtration markers should be considered when more accurate ascertainment will impact treatment decisions 2
The MDRD equation systematically underestimates measured GFR at higher values (>60 mL/min/1.73 m²), which is why CKD-EPI is preferred in this range 1
Ensure creatinine was measured using enzymatic methods where possible, as this is more specific than the Jaffe method and has a coefficient of variation <2.3% 1