Kidney function estimate using the MDRD study equation
This calculator estimates glomerular filtration rate from serum creatinine, age, sex, and the historical ethnicity multiplier used in the original MDRD equation.
For routine reporting today, race-free CKD-EPI is generally preferred by kidney organizations. Use this tool for reference, education, historical comparison, or legacy workflows.
What this page includes
- Advanced MDRD eGFR calculation
- Optional BSA-adjusted absolute estimate
- Stage classification and interpretation
- CSV and PDF export tools
- Formula, instructions, example table, and FAQs
Calculator form
Example data table
| Patient | Age | Sex | Creatinine | Legacy factor | eGFR | Stage |
|---|---|---|---|---|---|---|
| Case A | 58 | Female | 1.60 mg/dL | No | 33.79 | G3b |
| Case B | 44 | Male | 1.10 mg/dL | No | 71.49 | G2 |
| Case C | 70 | Female | 2.40 mg/dL | Yes | 25.13 | G4 |
Formula used
The traditional four-variable MDRD study equation in conventional units is:
eGFR = 175 × (SCr)-1.154 × (Age)-0.203 × 0.742 if female × 1.212 if the original Black/African American factor is applied
Where eGFR is expressed in mL/min/1.73 m², serum creatinine uses standardized mg/dL, and age is entered in years. If creatinine is entered in µmol/L, this page converts it to mg/dL first.
When height and weight are supplied, the page also estimates body surface area with the Mosteller formula:
BSA = √((height in cm × weight in kg) / 3600)
The de-indexed absolute filtration estimate is then:
Absolute eGFR = indexed eGFR × BSA / 1.73
MDRD is an older equation. Current kidney guidance generally favors race-free CKD-EPI for routine reporting, and MDRD is less reliable when results are above 60 mL/min/1.73 m². citeturn877847search0turn877847search2turn877847search7turn877847search11
How to use this calculator
- Enter adult age, sex, and serum creatinine.
- Select the creatinine unit used by the laboratory report.
- Choose whether to apply the original MDRD ethnicity multiplier for legacy comparison.
- Optionally add height and weight to estimate body surface area and a de-indexed filtration value.
- Pick the albuminuria category if available for fuller kidney risk context.
- Press Calculate eGFR to show the result above the form.
- Use the export buttons to save a CSV or PDF summary.
Why MDRD still matters
MDRD remains useful when reviewing older charts, comparing historical laboratory reports, teaching nephrology basics, or matching legacy clinical workflows. Still, newer guidance recommends race-free CKD-EPI for most adult reporting because it improves standardization and avoids race-based adjustment in routine care. citeturn877847search2turn877847search5
Frequently asked questions
1. What does MDRD eGFR estimate?
It estimates kidney filtration from serum creatinine, age, sex, and the original MDRD demographic adjustments. The result is normalized to 1.73 m² body surface area.
2. Is MDRD the preferred equation today?
Usually no. Kidney organizations generally recommend race-free CKD-EPI for current adult reporting. MDRD is still useful for reference, education, and comparison with older reports. citeturn877847search2turn877847search5
3. Why can results above 60 be misleading?
MDRD becomes less accurate at higher filtration levels. Because of that limitation, laboratories historically often reported values above 60 as “≥60” instead of a precise number. citeturn877847search7
4. What is the de-indexed absolute eGFR?
It adjusts the standardized result for a patient’s estimated body surface area. This can help when a body-size-specific value is needed for contextual review.
5. Can I use this page for children?
No. MDRD is intended for adults. Pediatric kidney estimation uses different formulas and clinical interpretation rules.
6. Should I use the legacy ethnicity multiplier?
Use it only when reproducing historical MDRD reports or legacy workflows. Current routine reporting generally avoids race-based adjustment and favors race-free CKD-EPI. citeturn877847search2turn877847search6
7. Does eGFR alone diagnose chronic kidney disease?
No. Clinicians interpret eGFR together with urine albumin, trend over time, symptoms, medications, imaging, and other laboratory results.