Pediatric Glomerular Filtration Rate Calculator - Bedside Schwartz eGFR

A pediatric glomerular filtration rate calculator turns a child's height and serum creatinine into an estimated GFR (eGFR) using the bedside Schwartz 2009 equation, the equation pediatric nephrologists use most. The result is the pediatric glomerular filtration rate in mL/min/1.73 m², paired with a KDIGO pediatric CKD stage. The calculator is built for children 1 to 18 (the bedside Schwartz 2009 equation was derived in 1 to 16), accepts creatinine in mg/dL or µmol/L, and offers cystatin C.

• • Pre-clinic review: enter a recent height and creatinine so the family sees a number and KDIGO stage before the visit.
• • Reviewing a recent lab result: re-enter a recent outpatient height and creatinine, because creatinine-based eGFR is most reliable when the child is at their usual baseline, not during an acute illness.
• • Tracking after diagnosis: repeat the bedside Schwartz 2009 estimate each visit and watch the eGFR move with treatment and growth.
• • Switching to cystatin C: rerun with cystatin C when creatinine is unreliable (low muscle mass, amputation, or steroid use).

For the same visit, the calculator can also run the CKiD 2012 cystatin-C-only or combined equations, useful when one or both biomarkers are available.

The Glomerular Filtration Rate Calculator applies the race-free CKD-EPI 2021 equation to the same mL/min/1.73 m² unit, so a parent can compare adult and child numbers without rescaling.

The default is the 2009 CKiD bedside Schwartz: eGFR (mL/min/1.73 m²) equals 0.413 times height in centimeters divided by serum creatinine in mg/dL. The constant was derived in a multi-center study and is calibrated to IDMS-traceable enzymatic creatinine.

• 0.413: Fixed k constant from the 2009 CKiD derivation, calibrated to IDMS-traceable enzymatic creatinine in children 1 to 16.
• height: Standing height in cm. The equation scales with height because creatinine production tracks body length.
• serumCreatinine: Serum creatinine in mg/dL. Jaffe assays over-estimate; enzymatic or IDMS-traceable is preferred.

The two 2012 CKiD alternatives extend the same workflow. The cystatin-C-only equation is 70.69 times cystatin C in mg/L raised to -0.931, and the combined equation is 39.8 times four fractional powers (height/creatinine, 1.8/cystatin C, 30/BUN, height/1.40 m) with a male multiplier of 1.076. According to Schwartz GJ, J Am Soc Nephrol, 2012, both were validated in 643 children with CKD and showed better precision than creatinine alone.

The calculator applies the same KDIGO pediatric cut-offs to every equation, so the eGFR number, the G stage, and the percent-of-normal label move together when the inputs change.

According to Schwartz GJ, J Am Soc Nephrol, 2009, the updated bedside Schwartz equation estimates pediatric GFR as 0.413 times height in centimeters divided by serum creatinine in mg/dL.

Because the CKiD 2012 combined equation also takes a BUN value, the BUN Creatinine Ratio Calculator turns the same blood draw into a hydration and perfusion signal alongside the pediatric eGFR.

Four ideas drive every pediatric GFR result and keep the bedside Schwartz 2009 number from being read as a stand-alone diagnosis.

In practice the eGFR is a starting point, not a verdict: the same number in a teen with nephrotic syndrome and a 6-year-old recovering from diarrhea are read very differently.

Hypertension is a common companion of reduced pediatric GFR, and the Pediatric Blood Pressure Calculator reads the same age, sex, and height percentiles against the AAP chart, so a low eGFR and high blood pressure can be read together.

The form mirrors the order of a real pediatric chart: equation, demographics, then labs. Each input is checked against the same ranges pediatric nephrologists use, so results are reproducible visit to visit.

1. 1 Choose the equation: start with the bedside Schwartz 2009 (creatinine only). Switch to the CKiD 2012 cystatin C option when muscle mass is unreliable, or the combined option when both biomarkers are available.
2. 2 Enter age, sex, and height: use the most recent measured height. The calculator flags values outside 1 to 16, the bedside Schwartz 2009 derivation range.
3. 3 Enter serum creatinine with its unit: pick mg/dL or µmol/L. The calculator converts µmol/L to mg/dL by dividing by 88.4, and clamps small values to 0.1 mg/dL to prevent division by zero.
4. 4 Optionally enter cystatin C and BUN: for the CKiD 2012 equations. The cystatin C unit toggle converts mg/dL to mg/L, and BUN should be the lab's BUN, not total urea.
5. 5 Read the eGFR, stage, and percent: the result panel shows the eGFR in mL/min/1.73 m², the KDIGO G stage and description, and a percent of the age-appropriate normal of 110 mL/min/1.73 m².
6. 6 Note the age or assay flag: if the age is outside 1 to 16 or the equation was switched, the flag line names the change so the calculation matches the patient.

A 10-year-old, 140 cm, female with creatinine 0.7 mg/dL returns an eGFR of 82.6 mL/min/1.73 m², G2 (Mildly decreased), about 75% of normal. A repeat creatinine and urine check are typical.

When a reduced eGFR changes how a prescription is written, the Pediatric Dose Calculator reads the same age and weight into a mg/kg dose and a total mg amount, so the dosing conversation can happen in the same chart view as the eGFR.

The calculator compresses a CKiD equation, a KDIGO pediatric stage, and a unit-aware input into one screen, so a child's kidney function is easier to track over time.

• • Same unit as adult eGFR: the result is in mL/min/1.73 m², the same as the adult CKD-EPI eGFR calculator, so the numbers compare without rescaling.
• • Age-appropriate KDIGO stages: the eGFR is paired with a KDIGO G stage (G1 to G5) and a short label.
• • Three equations in one form: the bedside Schwartz 2009 and the CKiD 2012 equations share the same form.
• • Unit-aware inputs: creatinine accepts mg/dL or µmol/L and cystatin C accepts mg/L or mg/dL.
• • Percent-of-normal comparison: the eGFR is shown next to a percent of the age-appropriate normal of 110 mL/min/1.73 m², so an 80 reading is 73% of normal.

A stable eGFR is also useful between visits, because a child with a known baseline can be reviewed over the phone or in triage without a new blood draw.

For a child with eGFR below 60 mL/min/1.73 m² for three months or more, the Kidney Failure Risk Calculator turns the same age, sex, and lab values into a 2- and 5-year kidney failure risk that pairs with the bedside Schwartz 2009 number.

The eGFR can move several mL/min/1.73 m² based on small input changes. Five are common in real pediatric visits.

• • The bedside Schwartz 2009 number is a screening estimate, not a measured GFR. Iohexol, iothalamate, or EDTA plasma clearance is the most accurate confirmatory test when a precise GFR is required (for example, before chemotherapy dosing or living-donor evaluation).
• • The equation is not validated for infants under 1, and the calculator accepts 0.5 to 25 with an out-of-range flag below 1 or above 18. For adults, the race-free CKD-EPI 2021 equation in the adult glomerular filtration rate calculator is the recommended choice.

Children with changing muscle mass, amputation, or chronic steroid use are better screened with the CKiD 2012 cystatin-C-only or combined equations, since cystatin C is independent of muscle.

According to KDIGO CKD Evaluation and Management Guideline, the bedside Schwartz 2009 equation is the recommended creatinine-based eGFR for children, with the CKiD 2012 equations used when cystatin C is available.

A child transitioning to adult nephrology can be re-screened with the GFR Calculator once they cross 18, because the CKD-EPI 2021 equation is calibrated to the same mL/min/1.73 m² unit but uses an age decay that fits young adults.