Sex
Female
Height
ft
in
Serum Creatinine
mg/dL
Serum Cystatin C
mg/L
BUN
mg/dL
GFR
mL/min/1.73m²
GFR
mL/min/1.73m²
GFR
mL/min/1.73m²

Pediatric GFR Calculator - Glomerular Filtration Rate

By Bogna Haponiuk

This pediatric GFR calculator is a version of our GFR calculator that is targeted for patients who are 18 years old or younger. There is a substantial difference in how this indicator is calculated for adults and children; read on to discover what it is and become familiar with the proper formulas.

What is GFR?

Glomerular filtration rate, or GFR for short, is a test for determining kidney disease risk. It can be calculated from your blood test results.

The unit of GFR is mL/min/1.73m². The value 1.73m² is the standardized body area. Because the body area is different for kids at various ages, the equations listed below take into consideration the height factor.

How to calculate GFR

According to the National Kidney Foundation, there are three main ways to estimate the GFR of children. Our pediatric GFR calculator uses all of them so that you can compare all results and see whether all of them are in the normal range.

1. Creatinine-based “Bedside Schwartz” equation (2009)

This is the standard - and the best method - for estimating GFR in children aged 1-18. Since it was updated in 2009, it no longer returns overestimated results.

GFR = 41.3 * (height / Scr)

where:

  • height is expressed in meters; and
  • SCr is the level of standardized serum creatinine in mg/dL.

2. Cystatin C-based equation (2012)

This formula uses the level of serum cystatin C instead of the creatinine indicator. It is an excellent confirmatory test and a recommended one if the levels of creatinine are fluctuating.

eGFR = 70.69 * Scys-0.931

where:

  • Scys is the level of standardized serum cystatin C in mg/L.

3. Creatinine-Cystatin C-based CKiD equation (2012)

This test uses both creatinine and cystatin C indicators. It is an excellent confirmatory test, too.

GFR = 39.8 * (height/Scr)0.456 * (1.8/Scys)0.418 * (30/BUN)0.079 * a * (height/1.4)0.179

where:

  • height is expressed in meters;
  • a is a coefficient dependent on sex: 1 for females, 1.076 for males;
  • BUN is the level of blood urea nitrogen in mg/dL;
  • Scys is the level of standardized serum cystatin C in mg/L;
  • SCr is the level of standardized serum creatinine in mg/dL.

What levels of GFR are alarming?

The table below shows the typical values of GFR on different stages of kidney malfunction.

eGFR [mL/min/1.73m²] Kidney function
90 or above
No kidney damage or mild kidney damage with normal kidney function
60-89
Kidney damage with mild loss of kidney function
45-59
Mild to moderate loss of kidney function
30-45
Moderate to severe loss of kidney function
15-29
Severe loss of kidney function
Less than 15
Kidney failure
Bogna Haponiuk