KDIGO 2024

Pediatric eGFR Calculator (Bedside Schwartz 2009)

Estimate glomerular filtration rate in children using the Bedside Schwartz (2009) equation with KDIGO CKD staging.

Patient Information

30–250 cm
0.1–10 mg/dL

Optional. Original Schwartz Equation

Enable to use the older original Schwartz formula with age-based k coefficient.

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Frequently Asked Questions About eGFR & CKD in Children

eGFR (estimated glomerular filtration rate) measures how well the kidneys are filtering waste from the blood. It is the most commonly used test to estimate kidney function and stage chronic kidney disease (CKD). A lower eGFR indicates declining kidney function.

In children, accurate eGFR estimation is critical because age, size, and developmental changes affect creatinine metabolism differently than in adults. Early detection of reduced kidney function allows for intervention to slow CKD progression and prevent complications.

The Bedside Schwartz equation (updated 2009) estimates eGFR using height and serum creatinine: eGFR = 0.413 × height (cm) / Scr (mg/dL). This simplified form requires only height and creatinine, no age or sex dependency, making it practical for bedside use.

The 2009 update used updated creatinine assays (enzymatic rather than Jaffe), which made the original k coefficient of 0.55 obsolete. The new coefficient (0.413) was re-derived to maintain accuracy with modern assays. This equation is validated for children 1–16 years with CKD.

KDIGO (Kidney Disease: Improving Global Outcomes) staging divides CKD into 5 stages based on eGFR:

  • G1 (≥90): Normal or high. Kidney function is normal
  • G2 (60–89): Mild decrease. Kidney function mildly reduced
  • G3a (45–59): Mild to moderate decrease. Early CKD
  • G3b (30–44): Moderate to severe decrease. More advanced CKD
  • G4 (15–29): Severe decrease. Risk of kidney failure
  • G5 (<15): Kidney failure. May need dialysis or transplant

Lower stages require monitoring; higher stages need specialist care and may require medications or renal replacement therapy.

The Bedside Schwartz equation is less accurate in:

  • Acute kidney injury (AKI): Creatinine rises slowly; eGFR may overestimate function
  • Very young infants (<1 year): Creatinine metabolism is different
  • Extremes of muscle mass: Muscular children may have high creatinine despite normal GFR; obese or malnourished children may have low creatinine relative to function
  • Liver disease: Creatinine production is reduced
  • Severe malnutrition: Muscle mass is low

For these populations, cystatin C eGFR or measured GFR (inulin, iohexol clearance) may be more accurate. Always correlate with clinical context.

Serum creatinine (Scr) is a waste product of muscle metabolism filtered by the kidneys. When kidneys function normally, creatinine is cleared efficiently and blood levels remain stable. Higher serum creatinine indicates reduced kidney function.

In children, serum creatinine is lower than in adults because muscle mass is smaller. The eGFR equation corrects for this by using the creatinine-to-height ratio, acknowledging that a child with less muscle naturally produces less creatinine even with normal kidney function. This is why using adult creatinine cutoffs is inappropriate in pediatrics.

Monitoring frequency depends on CKD stage:

  • G1–G2 (eGFR ≥60): Annual monitoring if risk factors present; less frequent if no risk factors
  • G3a–G3b (eGFR 30–59): Every 3–6 months
  • G4 (eGFR 15–29): Every 1–3 months; prepare for renal replacement therapy
  • G5 (eGFR <15): Monthly or more; nephrology specialist care; renal replacement therapy required

More frequent monitoring is needed if: eGFR is declining rapidly, proteinuria is present, blood pressure is elevated, or there are metabolic complications.