Egfr Calculator

The eGFR (estimated Glomerular Filtration Rate) Calculator is an essential medical tool used to estimate kidney function. Your kidneys filter waste and excess fluids from your blood, and the eGFR is a key indicator of how well your kidneys are working. Healthcare providers commonly use this value to detect kidney disease early, monitor its progression, and guide treatment decisions.

eGFR (CKD-EPI) Calculator
mg/dL
years
CKD-EPI 2009 formula, units: mg/dL, age ≥ 18.
More info

How to Use the eGFR Calculator

Using the eGFR Calculator is simple:

  1. Enter Serum Creatinine – Input your latest blood creatinine value (usually in mg/dL or µmol/L).
  2. Input Age – Your current age in years.
  3. Select Sex – Male or Female.
  4. Select Race – Choose from options such as Black or Non-Black (some formulas adjust for race).
  5. Choose Units – Make sure serum creatinine units match your input.
  6. Click Calculate – Get your estimated glomerular filtration rate (eGFR) in mL/min/1.73 m² instantly.

Formula Used in eGFR Calculation

The most widely used formulas for calculating eGFR are:

1. CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) Equation

For serum creatinine in mg/dL: eGFR=141×min⁡(Scrκ,1)α×max⁡(Scrκ,1)−1.209×0.993Age×Adjustment FactoreGFR = 141 \times \min \left(\frac{S_{cr}}{\kappa}, 1\right)^{\alpha} \times \max \left(\frac{S_{cr}}{\kappa}, 1\right)^{-1.209} \times 0.993^{\text{Age}} \times \text{Adjustment Factor}eGFR=141×min(κScr​​,1)α×max(κScr​​,1)−1.209×0.993Age×Adjustment Factor

Where:

  • ScrS_{cr}Scr​ = serum creatinine
  • κ\kappaκ = 0.7 (female), 0.9 (male)
  • α\alphaα = -0.329 (female), -0.411 (male)
  • Adjustment Factor = 1.159 if Black, 1 otherwise
  • Age in years

2. MDRD (Modification of Diet in Renal Disease) Equation

eGFR=175×(Scr)−1.154×(Age)−0.203×(0.742 if female)×(1.212 if Black)eGFR = 175 \times (S_{cr})^{-1.154} \times (\text{Age})^{-0.203} \times (0.742 \text{ if female}) \times (1.212 \text{ if Black})eGFR=175×(Scr​)−1.154×(Age)−0.203×(0.742 if female)×(1.212 if Black)

Example Calculation Using CKD-EPI Formula

Patient Data:

  • Serum Creatinine: 1.1 mg/dL
  • Age: 55 years
  • Sex: Female
  • Race: Non-Black

Step 1: Identify parameters

  • κ=0.7\kappa = 0.7κ=0.7, α=−0.329\alpha = -0.329α=−0.329
  • Scrκ=1.10.7≈1.57\frac{S_{cr}}{\kappa} = \frac{1.1}{0.7} \approx 1.57κScr​​=0.71.1​≈1.57

Step 2: Calculate min and max terms

  • min⁡(1.57,1)=1\min(1.57, 1) = 1min(1.57,1)=1
  • max⁡(1.57,1)=1.57\max(1.57, 1) = 1.57max(1.57,1)=1.57

Step 3: Compute components

  • 1α=1−0.329=11^{\alpha} = 1^{-0.329} = 11α=1−0.329=1
  • 1.57−1.209≈0.5371.57^{-1.209} \approx 0.5371.57−1.209≈0.537
  • 0.99355≈0.6860.993^{55} \approx 0.6860.99355≈0.686

Step 4: Calculate eGFR eGFR=141×1×0.537×0.686×1=141×0.368=51.9 mL/min/1.73 m2eGFR = 141 \times 1 \times 0.537 \times 0.686 \times 1 = 141 \times 0.368 = 51.9 \text{ mL/min/1.73 m}^2eGFR=141×1×0.537×0.686×1=141×0.368=51.9 mL/min/1.73 m2

What Does Your eGFR Number Mean?

  • 90+ mL/min/1.73 m²: Normal kidney function
  • 60–89: Mildly decreased function (may be normal for some)
  • 45–59: Mild to moderate decrease (CKD stage 3a)
  • 30–44: Moderate to severe decrease (CKD stage 3b)
  • 15–29: Severe decrease (CKD stage 4)
  • <15: Kidney failure (CKD stage 5) — requires medical attention

Additional Information About eGFR

  • eGFR helps detect chronic kidney disease (CKD) early.
  • It is used to monitor kidney function over time.
  • Creatinine levels vary by muscle mass, so eGFR accounts for age, sex, and race.
  • Always discuss results with your healthcare provider for accurate diagnosis.
  • The eGFR Calculator is a screening tool and does not replace clinical evaluation.

20 Frequently Asked Questions (FAQs)

1. What is eGFR?
Estimated Glomerular Filtration Rate, a test measuring kidney function.

2. How is eGFR different from serum creatinine?
Serum creatinine is a lab value; eGFR estimates kidney function based on it plus other factors.

3. Why is race considered in the calculation?
Muscle mass differences can affect creatinine; race adjusts for that in formulas.

4. What units are used for eGFR?
mL/min/1.73 m² (milliliters per minute per 1.73 square meters body surface area).

5. Is eGFR accurate for all populations?
It’s an estimate; accuracy can vary, especially in very muscular or elderly individuals.

6. Can eGFR detect kidney disease early?
Yes, it’s a key screening tool for chronic kidney disease.

7. How often should eGFR be tested?
Depends on risk factors and health status; often yearly for at-risk patients.

8. What affects my serum creatinine level?
Muscle mass, diet, medications, and hydration status.

9. What if my eGFR is low?
Consult a healthcare provider for further testing and management.

10. Can I calculate eGFR at home?
With this calculator and lab results, yes, but interpret with professional advice.

11. Does the calculator work for children?
No, pediatric formulas differ.

12. Are there other kidney function tests?
Yes, including urine albumin and cystatin C tests.

13. Can dehydration affect eGFR?
Yes, it can raise creatinine and lower eGFR temporarily.

14. Does medication affect eGFR?
Certain drugs can impact kidney function and test results.

15. Can eGFR be used for transplant patients?
Yes, to monitor kidney health post-transplant.

16. Is eGFR affected by race controversies?
Some debate exists; newer calculators aim to remove race adjustments.

17. What should I do with my eGFR result?
Discuss with your doctor for diagnosis and care planning.

18. Is a high eGFR good?
Generally yes, indicates healthy kidneys.

19. Can eGFR be used for acute kidney injury?
It’s less reliable in acute cases; other tests are preferred.

20. Does body size affect eGFR?
The value is standardized for body surface area (1.73 m²).