Pediatric eGFR Calculator

Pediatric eGFR Calculator | Lab Tool

Pediatric eGFR Calculator

Estimation Method

Serum Creatinine mg/dL Standard range: 0.3–1.5 mg/dL (children)

Height cm Height in centimeters (measure recumbent for infants/toddlers)

Formula eGFR = 0.413 × Height / Scr Bedside Schwartz (2009) — most widely used for children 1–18 years

Serum Creatinine mg/dL

Height cm

Age years For infants < 1 year, use months (e.g., 0.5 for 6 months)

Gender

Preterm Status

Preterm infant (only for age < 1 year)

Check if the infant was born preterm (gestational age < 37 weeks)

k value 0.55 (Child (1-13 y)) Automatically determined from age, gender, and preterm status

Formula eGFR = k × Height / Scr Original Schwartz (1976) — k varies by age/gender

Serum Creatinine mg/dL

Height cm

Cystatin C mg/L Normal range: 0.50–1.00 mg/L

Formula eGFR = 0.413 × (Ht / Scr) × (CysC / 0.8)^−0.65 CKiD (2012) — combines creatinine and cystatin C for improved accuracy

eGFR

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mL/min/1.73m²

Step-by-Step Calculation

Click Calculate eGFR to see the detailed step-by-step analysis.

👉👉 Calculate now : MDRD eGFR Calculator

Complete Guide to Pediatric eGFR Estimation

Introduction

Estimated Glomerular Filtration Rate (eGFR) is a crucial laboratory parameter used to assess kidney function in children. It estimates the volume of blood filtered by the glomeruli per unit time, normalized to a standard body surface area of 1.73 m². Accurate eGFR calculation is essential for diagnosing, monitoring, and managing pediatric kidney disease.

What is eGFR?

eGFR is a calculated value that estimates how well the kidneys are filtering waste products from the blood. In children, eGFR is particularly important because kidney function changes with age, growth, and development. The glomerular filtration rate (GFR) is the gold standard for kidney function assessment, but it requires invasive procedures. eGFR provides a convenient, non-invasive alternative using readily available laboratory measurements.

Units: mL/min/1.73m² (normalized to body surface area)
Normal range (children): Typically 90–120 mL/min/1.73m²
Clinical use: CKD staging, drug dosing, monitoring disease progression

Why is Pediatric eGFR Important?

Accurate eGFR estimation in children is critical for several reasons:

Chronic Kidney Disease (CKD): Early detection and staging guide treatment decisions.
Drug Dosing: Many medications require dose adjustment based on kidney function.
Growth and Development: Kidney function changes with age, making pediatric-specific formulas essential.
Disease Monitoring: Serial eGFR measurements track disease progression or response to therapy.

How to Use the Pediatric eGFR Calculator

The tool offers three validated estimation methods:

Method 1: Bedside Schwartz (2009)

The most widely used pediatric eGFR formula. It requires serum creatinine and height only.

Formula: eGFR = 0.413 × Height / Scr

Scr: Serum creatinine (mg/dL)
Height: Height (cm)
Valid for: Children 1–18 years

This formula is recommended by the NKF-KDOQI guidelines for initial eGFR estimation in children.

Method 2: Original Schwartz (1976)

The original Schwartz formula uses age- and gender-specific k constants.

Formula: eGFR = k × Height / Scr

Patient Category	k Value
Preterm infant (< 1 year)	0.33
Term infant (< 1 year)	0.45
Child (1–13 years)	0.55
Adolescent male (13–18 years)	0.70
Adolescent female (13–18 years)	0.55

Method 3: CKiD (2012) with Cystatin C

The CKiD formula combines serum creatinine and cystatin C for improved accuracy, especially in children with CKD.

Formula: eGFR = 0.413 × (Ht / Scr) × (CysC / 0.8)^−0.65

Scr: Serum creatinine (mg/dL)
Ht: Height (cm)
CysC: Cystatin C (mg/L)
Valid for: Children with known or suspected CKD

Understanding eGFR Categories

eGFR (mL/min/1.73m²)	Category	CKD Stage
≥ 90	Normal	Stage 1
60–89	Mildly decreased	Stage 2
30–59	Moderate decrease	Stage 3
15–29	Severe decrease	Stage 4
< 15	Kidney failure	Stage 5

Tips for Accurate eGFR Estimation

Accurate Height Measurement: Use recumbent length for infants and toddlers; standing height for older children.
Serum Creatinine: Ensure the assay is calibrated to IDMS (isotope dilution mass spectrometry) for consistent results.
Choose the Right Formula: Bedside Schwartz is recommended for routine use. CKiD is preferred in CKD patients.
Age Considerations: The Bedside Schwartz formula is validated for children 1–18 years. For infants, use the Original Schwartz with appropriate k values.

Common Applications in Clinical Practice

CKD Staging: eGFR is the primary criterion for CKD staging in children.
Drug Dosing: Many medications (e.g., antibiotics, immunosuppressants) require dose adjustment based on eGFR.
Transplant Monitoring: Serial eGFR measurements track graft function after kidney transplantation.
Disease Progression: eGFR trends help assess response to therapy and disease progression.

Limitations and Considerations

Muscle Mass: Creatinine-based formulas are influenced by muscle mass, which varies with age, gender, and nutrition.
Acute Kidney Injury: eGFR formulas are validated for stable kidney function and may be inaccurate in acute settings.
Interference: Certain medications and conditions can affect serum creatinine levels independently of GFR.
Non-steady State: eGFR assumes steady-state creatinine, which may not hold in rapidly changing clinical situations.

Conclusion

The Pediatric eGFR Calculator provides a comprehensive, evidence-based approach to estimating kidney function in children. By offering three validated formulas, the tool accommodates various clinical scenarios and patient populations. Accurate eGFR estimation enables early detection of kidney disease, appropriate drug dosing, and effective monitoring of disease progression.

Clinical Note: eGFR is an estimation, not a direct measurement. Always interpret results in the context of the patient's clinical presentation, growth parameters, and laboratory trends. Consult a pediatric nephrologist for complex cases or when clinical decisions depend on precise GFR assessment.

Pediatric eGFR Calculator