Pediatric GFR Calculator

Calculate Glomerular Filtration Rate in children using established pediatric equations

Patient Information

years

Recommended for ages 1-18 years

Required for CKiD equation calculation

Standing height measurement

mg/dL

Standardized serum creatinine level

mg/L

For cystatin-based and combined equations

mg/dL

Required for combined CKiD equation

Input Warnings

⚠️ Bedside Schwartz equation is most accurate for ages 1-18 years
⚠️ Height outside typical pediatric range

GFR Calculations

Bedside Schwartz Equation (2009)

Primary Method
Enter height and serum creatinine to calculate

Cystatin C-based Equation (2012)

Confirmatory
Enter serum cystatin C to calculate

Combined CKiD Equation (2012)

Most Comprehensive
Enter all parameters (height, creatinine, cystatin C, BUN) to calculate

Example Calculations

10-Year-Old Child

Height: 140 cm (1.4 m)

Serum Creatinine: 0.7 mg/dL

Schwartz GFR: 41.3 × (1.4 / 0.7) = 82.6 mL/min/1.73m²

Interpretation: Kidney damage with mild loss of function

Healthy 8-Year-Old

Height: 125 cm (1.25 m)

Serum Creatinine: 0.5 mg/dL

Schwartz GFR: 41.3 × (1.25 / 0.5) = 103.3 mL/min/1.73m²

Interpretation: Normal kidney function

GFR Interpretation

90+

Normal

No kidney damage or mild damage with normal function

60-89

Mild Loss

Kidney damage with mild loss of function

45-59

Moderate Loss

Mild to moderate loss of function

30-44

Severe Loss

Moderate to severe loss of function

15-29

Very Severe

Severe loss of kidney function

<15

Kidney Failure

Kidney failure - dialysis/transplant needed

Calculation Methods

📊

Bedside Schwartz (2009)

Standard method, ages 1-18 years

🧪

Cystatin C-based (2012)

Alternative when creatinine fluctuates

🔬

Combined CKiD (2012)

Most comprehensive, uses multiple parameters

Understanding Pediatric GFR

What is GFR?

Glomerular Filtration Rate (GFR) measures how well the kidneys filter blood. In children, kidney function assessment requires age-specific calculations that account for growth and development. The unit mL/min/1.73m² standardizes results to body surface area.

Why Use Pediatric-Specific Equations?

  • Children have different muscle mass affecting creatinine levels
  • Growth and development influence kidney function
  • Height is a better predictor than weight in children
  • Adult equations overestimate GFR in pediatric patients

Calculation Methods

Bedside Schwartz (2009)

GFR = 41.3 × (height in meters / serum creatinine)

Primary method for ages 1-18. Updated formula provides more accurate results than earlier versions.

Cystatin C-based (2012)

eGFR = 70.69 × Cystatin C^(-0.931)

Useful when creatinine levels are fluctuating or unreliable.

Clinical Note: Always consider clinical context when interpreting GFR results. Trends over time are often more important than single measurements.

Important Medical Disclaimer

This calculator is provided for educational and informational purposes only. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. Pediatric kidney function assessment requires clinical expertise and should always be interpreted by qualified healthcare professionals in the context of the patient's overall clinical picture. GFR calculations are screening tools and may not reflect actual kidney function in all cases. Always consult with a pediatric nephrologist for comprehensive kidney function evaluation in children.