Schwartz eGFR Calculator — Pediatric Kidney Function Assessment
The Bedside Schwartz eGFR formula estimates glomerular filtration rate in children and adolescents aged 0-21 years using serum creatinine, height, age, and sex. It is the most widely used equation for pediatric kidney function assessment.
About
The Bedside Schwartz eGFR equation, developed by Dr. George Schwartz and colleagues, is the standard method for estimating GFR in children. It uses a k constant that varies by age and sex: 0.33 for low birth weight infants <1 year, 0.45 for children 1-12 years, 0.55 for females 13-21 years, and 0.70 for males 13-21 years. The formula is: eGFR = (k × height in cm) / (serum creatinine in mg/dL). Results are interpreted using standard CKD staging: >90 normal, 60-89 mildly reduced, 30-59 moderately reduced, 15-29 severely reduced, <15 kidney failure.
Formula
eGFR = (k × height in cm) / (serum creatinine in mg/dL)
The k value varies by age and sex: k=0.33 for low birth weight infants <1 year, k=0.45 for children 1-12 years, k=0.55 for females 13-21 years, k=0.70 for males 13-21 years. The result is in mL/min/1.73m².
Score Interpretation
The Schwartz eGFR equation is essential for pediatric kidney function assessment. Chronic kidney disease affects approximately 1 in 10,000 children, but early detection is critical for preventing progression to end-stage renal disease. The Bedside Schwartz formula provides a simple, reliable estimate of GFR without requiring 24-hour urine collection. Serial measurements allow monitoring of disease progression and response to interventions. Accurate GFR estimation is also crucial for medication dosing in children with kidney disease.
Normal — 90+
eGFR ≥90 mL/min/1.73m². Normal kidney function.
Management: No specific intervention needed based on eGFR. Routine pediatric health maintenance.
Mildly Reduced — 60–89
eGFR 60-89 mL/min/1.73m². Mildly reduced kidney function.
Management: Monitor renal function every 6-12 months. Avoid nephrotoxic medications.
Moderately Reduced — 30–59
eGFR 30-59 mL/min/1.73m². Moderately reduced kidney function.
Management: Refer to pediatric nephrology. Monitor every 3-6 months. Monitor blood pressure.
Severely Reduced — 15–29
eGFR 15-29 mL/min/1.73m². Severely reduced kidney function.
Management: Urgent pediatric nephrology referral. Evaluate for renal replacement therapy.
Kidney Failure — 0–14
eGFR <15 mL/min/1.73m². Kidney failure.
Management: Urgent nephrology evaluation. Initiate or plan renal replacement therapy.
Reference Ranges
| Population | Normal Range | Notes |
|---|---|---|
| Children 0-21 years | ≥90 mL/min/1.73m² | Normal GFR decreases slightly with age in adolescence |
Dr. Khaled Hassan
Dr. Khaled is a cardiology consultant with experience in acute cardiac care.
View medical review board & editorial policy →Example Calculation
A 6-year-old boy (k=0.45): height 115 cm, creatinine 0.5 mg/dL. eGFR = (0.45 × 115) / 0.5 = 103.5 mL/min/1.73m² — Normal kidney function.
Related Conditions
Common Mistakes
Using Schwartz formula for adults >21 years
The Schwartz formula is validated for children and adolescents aged 0-21 years. For adults, use CKD-EPI or MDRD equations.
Using incorrect k value for age and sex
Always verify the correct k value based on age group and sex before calculating.
Frequently Asked Questions
What is the difference between Schwartz and CKD-EPI?
Can Schwartz eGFR be used for drug dosing?
References
- Schwartz GJ, Muñoz A, Schneider MF, et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol. 2009;20(3):629-637. PubMed
- KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD (2024)