Neonatal eGFR

Creatinine and height equation for term-born neonates

Biomarkers
Creatinine
Validated for
0–4 weeks
Inputs
Age, Height, Creatinine
Reports
mL/min/1.73 m²
Published
2022

The eGFR guide explains which equation the calculator suggests and indexed and absolute GFR.

Formula

eGFR=0.31×heightSCr\text{eGFR} = 0.31 \times \frac{\text{height}}{\text{SCr}}

As text: eGFR = 0.31 × height/SCr

Constants

SymbolMeaningValue
0.31Neonatal coefficient
HeightCrown–heel length (input)cm
ScrS_{cr}Serum creatinine (enzymatic assay) (input)mg/dL

How it was developed

A meta-analysis of 48 studies combined individual and aggregated data: 978 GFR measurements in 881 term-born neonates, by inulin, mannitol, ⁵¹Cr-EDTA or creatinine clearance. Reference values came from individual data on 367 neonates; least-squares analysis of these against eGFR from normative enzymatic creatinine and median CDC growth-chart height gave a coefficient of 0.308, rounded to 0.31.

Clinical notes

  • Schwartz form with a coefficient refitted for term-born neonates
  • Coefficient fitted to enzymatic serum creatinine in mg/dL
  • Externally validated in critically ill term-born neonates against iohexol GFR

Limitations

  • Not developed in preterm neonates
  • Not developed beyond 28 days of postnatal age
  • Uncertain in the youngest neonates while maternal creatinine clears
  • Not yet confirmed in a large neonatal cohort with measured GFR

References

  1. Smeets NJL, IntHout J, van der Burgh MJP, et al. Maturation of GFR in term-born neonates: An individual participant data meta-analysis. J Am Soc Nephrol. 2022;33(7):1277-1292. doi:10.1681/ASN.2021101326
  2. Smeets NJL, Teunissen EMM, van der Velden K, et al. Glomerular filtration rate in critically ill neonates and children: creatinine-based estimations versus iohexol-based measurements. Pediatr Nephrol. 2023;38(4):1087-1097. doi:10.1007/s00467-022-05651-w

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