The Cardiovascular
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Kinetic Estimated Glomerular Filtration Rate (keGFR)

Estimates GFR when serum creatinine is changing acutely, before a steady state.

Kinetic Estimated Glomerular Filtration Rate (keGFR)
Baseline (steady-state) eGFR
mL/min/1.73m2
Baseline (steady-state) serum creatinine
mg/dL
First serum creatinine
mg/dL
Second serum creatinine
mg/dL
Time between the two creatinines
hours
Max creatinine rise per day if GFR were zero
mg/dL/day
Complete the fields above to see the result.

When to use

  • Estimating GFR in acute kidney injury when creatinine has not yet reached a steady state.

Formula

keGFR = (baseline SCr x baseline eGFR / mean SCr) x [1 - (24 x (SCr2 - SCr1)) / (hours between samples x max creatinine rise per day)]. Max rise is commonly taken as 1.5 mg/dL/day.

Pearls and pitfalls

  • A rising creatinine drives keGFR below the steady-state estimate; a falling creatinine drives it above.
  • Assumes both creatinine values use the same units; the default maximal rise reflects anuric creatinine generation.

References

  1. Chen S. J Am Soc Nephrol. 2013;24(6):877-88.