maratoolMDRD vs CKD-EPI
A side-by-side comparison of MDRD GFR Calculator and CKD-EPI Creatinine Clearance Calculator.
MDRD (Modification of Diet in Renal Disease, 2000) and CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration, 2009; race-free update 2021) both estimate glomerular filtration rate from serum creatinine, age, and sex. CKD-EPI was developed specifically to improve accuracy at higher GFR values where MDRD systematically underestimates kidney function — and is now the KDIGO-recommended and lab-reported standard.
When to use MDRD GFR Calculator
Use MDRD only for comparison with older literature, archived patient records, or institutional protocols still calibrated to MDRD. MDRD underestimates GFR in patients with near-normal renal function, leading to false CKD diagnoses and inappropriate dose adjustments.
When to use CKD-EPI Creatinine Clearance Calculator
Use CKD-EPI 2021 as the default for all eGFR estimation. It performs better at GFR > 60 mL/min/1.73 m², is the current KDIGO standard, and is what virtually all clinical labs report. The 2021 race-free version removed the previous race coefficient.
Side-by-side comparison
| MDRD GFR | CKD-EPI Creatinine Clearance | |
|---|---|---|
| Year published | 2000 | 2009, race-free 2021 |
| Inputs | Age, sex, race, creatinine | Age, sex, creatinine (race removed 2021) |
| Accuracy at GFR > 60 | Underestimates | Accurate |
| Accuracy at GFR < 60 | Similar to CKD-EPI | Similar to MDRD |
| Current standard? | No — superseded | Yes (KDIGO 2024) |
| Reported on lab panels | Mostly retired | Yes |
| Includes race? | Yes (Black/non-Black coefficient) | No (removed in 2021) |
Bottom line
Use CKD-EPI 2021. MDRD is historical — keep it for reading older studies but not for current clinical decisions.
Frequently asked questions
Why did MDRD underestimate GFR at higher values?
MDRD was derived in patients with CKD, so its calibration was anchored at low GFR. It systematically pulls high-GFR values down toward the CKD range, generating false-positive CKD diagnoses in healthy people.
When was the race coefficient removed?
CKD-EPI dropped the race coefficient in 2021 after NKF/ASN concluded race should not be used as a biological variable. Labs adopted the 2021 race-free equation broadly in 2022.
Do I need to recalculate older eGFR values?
Generally no for current management — use the most recent (CKD-EPI 2021) value. For research or audit, document which equation produced a given historical value because the differences can be clinically meaningful.
What about cystatin C-based equations?
KDIGO 2024 recommends a combined creatinine + cystatin C equation (CKD-EPIcr-cys) when better accuracy is needed — for example, in transplant donors, oncology dosing, or when creatinine is unreliable (very low or very high muscle mass).