MDRD GFR Equation

What This Calculator Measures

Estimates glomerular filtration rate (eGFR) using the 4-variable MDRD equation, primarily encountered in older laboratory reports and historical comparisons.

How to Use

1. Enter the patient's age, sex, and serum creatinine (mg/dL).
2. Review the estimated eGFR and the corresponding CKD G stage.
3. For new clinical decisions, prefer the CKD-EPI 2021 equation when available.

Interpretation Guide

MDRD eGFR is interpreted using the same KDIGO G stages as CKD-EPI: G1 ≥ 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, and G5 < 15 mL/min/1.73 m². The equation applies a female adjustment factor (× 0.742).

Clinical Significance

The MDRD equation made eGFR reporting practical and remains important for interpreting older laboratory results and understanding why CKD-EPI has replaced it.

When to Use

• Comparing with older laboratory reports that still report MDRD eGFR
• Historical interpretation of eGFR trends
• Where CKD-EPI is unavailable

When Not to Use

• For new clinical decisions when CKD-EPI is available
• For medication dosing without drug-specific guidance (Cockcroft-Gault is commonly referenced)
• In acute kidney injury with unstable creatinine
• At extremes of body size or muscle mass without clinical correlation

Limitations

• Tends to underestimate GFR when the true GFR is above 60 mL/min/1.73 m².
• Was developed in patients with known CKD and is less accurate in healthy individuals.
• Values may differ from CKD-EPI; trends should be compared within the same equation.
• Less accurate at extremes of muscle mass and body habitus.

Worked Example

A 65-year-old woman has a serum creatinine of 1.1 mg/dL.

eGFR ≈ 175 × 1.1^-1.154 × 65^-0.203 × 0.742 ≈ 50 mL/min/1.73 m², corresponding to CKD stage G3a (45–59).

Evidence

Source

Nephrology

Reference

Levey AS, Bosch JP, Lewis JB, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Intern Med. 1999;130(6):461-470.

Reviewed By

MedCalcHub Clinical Team

Version

1.0

Updated

2026-08

1. Levey AS, et al. Ann Intern Med. 1999;130(6):461-470.
2. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease.

References

1. Levey AS, Bosch JP, Lewis JB, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Intern Med. 1999;130(6):461-470. (Original Description)
2. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. (Guideline)

Frequently Asked Questions