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MDRD GFR Equation
Modification of Diet in Renal Disease — 4-variable equation
Patient Parameters
Enter 0.1–30
Enter 18–120
—
mL/min/1.73m²
| Stage | GFR | Description | Action |
|---|---|---|---|
| G1 | ≥ 90 | Normal/High | Standard dosing; monitor |
| G2 | 60–89 | Mildly decreased | Minimal dose adjustment |
| G3a | 45–59 | Mild-moderate decrease | Dose adjustments needed |
| G3b | 30–44 | Moderate-severe decrease | Avoid nephrotoxins |
| G4 | 15–29 | Severely decreased | Prepare for RRT |
| G5 | < 15 | Kidney failure | Dialysis/transplant |
MDRD 4-variable:
GFR = 175 × (SCr)^(−1.154) × (Age)^(−0.203) × 0.742 [if female] × 1.212 [if African American]
GFR = 175 × (SCr)^(−1.154) × (Age)^(−0.203) × 0.742 [if female] × 1.212 [if African American]
Limitation: MDRD significantly underestimates GFR when true GFR >60 mL/min/1.73m². CKD-EPI 2021 is preferred for all patients. MDRD reports GFR as ">60" when calculated above that threshold. Race-based multiplier (African American) is included for historical reference but race-free CKD-EPI 2021 is now recommended.
