Kidney Failure Risk Calculator
Estimate two- and five-year kidney failure risk with the four-variable KFRE.
Four-variable KFRE
For adults with chronic kidney disease stages 3 to 5; use current, stable laboratory values.
About the Kidney Failure Risk Equation
The Kidney Failure Risk Equation, commonly called KFRE, estimates the probability that an adult with chronic kidney disease will need dialysis or a kidney transplant within a defined time. The four-variable model uses age, sex, estimated glomerular filtration rate, and urine albumin-to-creatinine ratio. It combines information about current filtration and kidney damage into one validated risk estimate that can support conversations about monitoring, nephrology referral, vascular access planning, and transplant evaluation.
Enter eGFR in milliliters per minute per 1.73 square meters and urine ACR in milligrams per gram. If a laboratory reports ACR in milligrams per millimole, convert it before using this version. Values should ideally represent a stable clinical period. Acute kidney injury, dehydration, a urinary infection, strenuous exercise, menstruation, or a rapidly changing creatinine can make a single result misleading. Repeating laboratory tests may be appropriate before important decisions are made.
The calculator implements the published North American four-variable coefficients and baseline survival values. Risk is not the same as certainty. A low percentage does not mean progression is impossible, and a high percentage does not show exactly when kidney failure will occur. Treatment of blood pressure, diabetes, albuminuria, cardiovascular risk, and other reversible factors may alter a person's future course. Competing health risks and differences between populations also affect interpretation.
KFRE is generally intended for adults with stage 3 to 5 chronic kidney disease and is not a screening test for people with normal kidney function. It should not be applied uncritically to children, pregnancy, kidney transplant recipients, or acute kidney injury. A clinician can interpret the estimate alongside the eGFR trend, cause of kidney disease, symptoms, comorbidities, treatment preferences, and local referral thresholds. Never delay urgent assessment because an online score appears low. Severe shortness of breath, confusion, chest pain, marked swelling, very low urine output, or dangerous electrolyte abnormalities require prompt medical care.
KFRE examples
| Clinical inputs | Approximate risk | Context |
|---|---|---|
| Male, 65; eGFR 28; ACR 300 mg/g | 2-year 6.5%; 5-year 23.0% | Discuss nephrology follow-up and trend |
| Female, 50; eGFR 40; ACR 100 mg/g | 2-year 1.2%; 5-year 4.5% | Continue risk-factor treatment and monitoring |
| Male, 75; eGFR 18; ACR 900 mg/g | 2-year 23.8%; 5-year 65.0% | May support kidney replacement planning |
How to use the KFRE calculator
- Select the patient's sex and enter age in years.
- Enter a stable, current eGFR value.
- Enter urine albumin-to-creatinine ratio in mg/g.
- Calculate and discuss both time horizons with a qualified clinician.
Kidney failure risk FAQ
What outcome does KFRE predict?
It predicts treated kidney failure, usually defined as dialysis or kidney transplantation. It does not predict every fall in eGFR or acute kidney injury.
Can I use ACR in mg/mmol?
Not directly in this calculator because it expects mg/g. Convert the laboratory value accurately before entering it.
Why are eGFR and ACR both needed?
eGFR reflects filtration while albuminuria reflects kidney damage. Together they predict progression better than either measure alone.
Does a high score mean dialysis is inevitable?
No, the output is a probability over a fixed period. Treatment, competing events, and changes in kidney function can alter the outcome.
When should KFRE be repeated?
It may be repeated when stable eGFR or ACR changes meaningfully. The appropriate interval depends on CKD severity and the treating clinician's plan.