MDRD 4 eGFR Calculator
Estimate glomerular filtration rate (eGFR) in mL/min/1.73m² using the 4-variable MDRD equation.
What is the MDRD 4 calculator?
The MDRD 4 calculator estimates kidney function by calculating eGFR (estimated glomerular filtration rate) from four variables: age, sex, serum creatinine, and an optional legacy race coefficient. This formula came from the Modification of Diet in Renal Disease study and has been widely used in clinical practice for many years.
Results are expressed as mL/min/1.73m², which normalizes kidney filtration to a standard body surface area.
MDRD 4 equation
If your creatinine value is entered in µmol/L, the calculator converts it to mg/dL using: mg/dL = µmol/L ÷ 88.4.
How to use this calculator
- Enter age in years.
- Select sex.
- Enter serum creatinine and choose the correct unit.
- Choose whether to apply the legacy Black race coefficient.
- Click Calculate eGFR.
eGFR interpretation guide (KDIGO categories)
| Category | eGFR (mL/min/1.73m²) | General Meaning |
|---|---|---|
| G1 | ≥ 90 | Normal or high (if no other kidney damage markers) |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mild to moderate decrease |
| G3b | 30–44 | Moderate to severe decrease |
| G4 | 15–29 | Severely decreased |
| G5 | < 15 | Kidney failure range |
MDRD vs CKD-EPI
When MDRD is useful
MDRD remains useful for historical comparisons and in settings where older reporting standards are still in use.
Where MDRD has limitations
MDRD may be less accurate at higher GFR values and in certain populations. Many labs now favor CKD-EPI equations for improved performance across wider ranges.
Clinical caveats
- eGFR is an estimate, not a direct measurement.
- Acute kidney injury, unusual muscle mass, pregnancy, or severe illness can reduce accuracy.
- Interpret eGFR alongside urinalysis, albumin-creatinine ratio, trend over time, and clinical context.
Bottom line
This MDRD 4 calculator gives a fast estimate of kidney function and kidney disease stage category. It is best used as a screening and monitoring aid, not as a standalone diagnosis tool. Always confirm with a qualified healthcare professional.