eGFR Calculation for a 53-Year-Old Male with Creatinine 111 µmol/L
Use the MDRD equation to calculate eGFR: eGFR = 175 × (creatinine in mg/dL)^-1.154 × (age)^-0.203, which yields approximately 68 mL/min/1.73 m² for this patient. 1
Converting Creatinine Units
- First, convert creatinine from 111 µmol/L to mg/dL by dividing by 88.4, which equals approximately 1.26 mg/dL 1, 2
MDRD Formula Application
The MDRD equation is the most widely validated and recommended formula for estimating GFR in adults: 1
Formula: eGFR = 175 × (serum creatinine)^-1.154 × (age)^-0.203 × (0.742 if female) × (1.210 if Black) 1, 3
For this 53-year-old non-Black male with creatinine 1.26 mg/dL:
- eGFR = 175 × (1.26)^-1.154 × (53)^-0.203
- eGFR ≈ 68 mL/min/1.73 m² 1
Clinical Interpretation
This eGFR of 68 mL/min/1.73 m² indicates Stage 2 CKD (mild kidney dysfunction with kidney damage) or normal kidney function if no other evidence of kidney damage exists 1, 3
An eGFR above 60 mL/min/1.73 m² generally represents preserved kidney function, though values between 60-89 mL/min/1.73 m² warrant evaluation for other markers of kidney damage such as albuminuria 1, 3
Alternative Formula Consideration
The CKD-EPI equation provides better accuracy than MDRD, especially at higher GFR values, though the MDRD remains the most widely validated formula 1
The Cockcroft-Gault formula can overestimate creatinine clearance and is less accurate than MDRD for estimating GFR 3, 4
Important Caveats
Serum creatinine alone should never be used to assess kidney function because it is affected by muscle mass, age, sex, dietary protein intake, and creatinine secretion beyond GFR 1, 5
The MDRD equation has limitations including lack of validation in those older than 70 years and systematic underestimation of measured GFR at higher values 1
Enzymatic methods for creatinine measurement are more specific than the Jaffé method, and if using enzymatic methods with traditional formulas, consider adding 0.2 mg/dL to the creatinine value 1, 2