Kinetic Estimated Glomerular Filtration Rate (keGFR)
Kinetic eGFR Calculator
mg/dL
mg/dL
mL/min/1.73m²
Kinetic eGFR:
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mL/min/1.73m²
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Formula: KeGFR = Baseline eGFR × (Baseline Cr / Current Cr).
Estimates GFR in patients with acutely changing creatinine.
Why Use
Other equations estimating GFR ( Cockcroft-Gault , MDRD ) have limited accuracy when creatinine is changing acutely.
Formula
Take two serum creatinine measurements (Cr 1 and Cr 2 ), at two different time points (time 1 and time 2 ). where variables are as follows: Variable* Definition Cr baseline Baseline creatinine, mg/dL CrCl Initial creatinine clearance, mL/min (by MDRD equation) Cr mean Average of Cr 1 and Cr 2 time 2 – time 1 Time between measured Cr 2 and Cr 1 , hrs *The second portion of the equation, i.e., 1 – [(24 x (Cr 2 – Cr 1 )) / ((time 2 – time 1 ) x 1.5)] , is a multiplier limited to 0-1. Note: formula assumes US units. For SI formula, see O’Sullivan 2017 .
Advice
While estimated GFR (by a validated equation) is adequate for most clinical scenarios, measured GFR is still considered the gold standard. Remember, eGFR is an estimate of kidney function, but is not included in the definition of AKI.
More Information
Interpretation: KeGFR of 30 mL/min is 90% specific (71% sensitive) for AKI, according to one small retrospective study ( O'Sullivan 2017 ).