What is the MDRD equation?

The Modification of Diet in Renal Disease (MDRD) study equation estimates GFR from serum creatinine, age, sex, and race. The 4-variable form is: eGFR = 175 × Scr^(−1.154) × Age^(−0.203) × 0.742 (if female) × 1.212 (if African American).

How does MDRD differ from CKD-EPI?

The CKD-EPI 2021 equation is more accurate at higher GFR values (above 60 mL/min/1.73 m²) and does not include a race variable. MDRD tends to underestimate GFR in healthier kidneys, so CKD-EPI is now the preferred formula. MDRD remains widely cited in older literature and some clinical systems.

Why does race affect the MDRD result?

The original MDRD study found higher average measured GFR among African American participants for a given creatinine level, likely due to differences in muscle mass and creatinine generation. The 1.212 multiplier reflects that finding. Many institutions are moving away from race-based equations; check your local guidelines.

What creatinine units should I use?

Enter creatinine in mg/dL (US standard) or µmol/L (SI). The calculator converts µmol/L to mg/dL automatically by dividing by 88.4 before applying the formula.

Is this tool suitable for children?

No. The MDRD equation was derived in adults and is not validated for patients under 18. Use the Schwartz equation for pediatric GFR estimation.

What do the KDIGO stages mean?

KDIGO stages: G1 ≥ 90 (normal or high), G2 60–89 (mildly decreased), G3a 45–59 (mild-to-moderately decreased), G3b 30–44 (moderately-to-severely decreased), G4 15–29 (severely decreased), G5 < 15 (kidney failure). Staging requires albuminuria data for full KDIGO classification.

eGFR MDRD Calculator

Enter serum creatinine, age, sex, and race to calculate eGFR via the 4-variable MDRD equation and map the result to a KDIGO CKD stage.

Patient Parameters

Serum Creatinine

Age (years)

Biological Sex

Male Female

Race

Other African American

The MDRD equation applies a 1.212 multiplier for African American patients.

Enter patient data and click Calculate

Results include eGFR value, CKD stage, and clinical interpretation.

Summary

The MDRD (Modification of Diet in Renal Disease) equation is a widely used formula for estimating GFR from serum creatinine, age, sex, and race. This calculator applies the 4-variable MDRD formula — eGFR = 175 × Scr^(−1.154) × Age^(−0.203) × 0.742 (if female) × 1.212 (if African American) — and maps the result to KDIGO G1–G5 chronic kidney disease stages with clinical context. Although the newer CKD-EPI 2021 equation is now preferred, the MDRD formula remains in widespread clinical and research use.

How it works

Enter the serum creatinine value from a blood test and select the unit (mg/dL or µmol/L).
Enter the patient age in years (18 or older).
Select biological sex — the MDRD equation applies a 0.742 coefficient for females.
Select race — the equation applies a 1.212 coefficient for African American patients.
Click Calculate to compute eGFR using the 4-variable MDRD formula.
The result is displayed with the corresponding KDIGO CKD stage and a brief clinical interpretation.

Use cases

Estimate kidney function in clinical and research settings using the established MDRD formula.
Stage chronic kidney disease (CKD G1–G5) per KDIGO guidelines.
Compare MDRD eGFR results against CKD-EPI values when both are reported.
Assess renal function for medication dose adjustments requiring GFR thresholds.
Educate medical students and trainees on the MDRD equation coefficients.
Screen patients with diabetes, hypertension, or cardiovascular disease for kidney involvement.
Reproduce published MDRD-based research calculations at the bedside.
Track longitudinal eGFR trends in patients with chronic renal insufficiency.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu