Drug Dosing in Renal Diseases: Estimation of Glomerular Filtration Rate Based on Serum Creatinine Concentration

Glomerular filtration rate, GFR, can be estimated from serum creatinine using diet modification in renal disease or MDRD formula and the chronic kidney disease–epidemiology collaboration or CKD–EPI equation.

These were developed based on serum creatinine and incorporate adjustments for age, sex, and race.

The MDRD equation does not require weight or height measurements and is normalized to the body surface area.

This method is more accurate for older and obese people than the healthy subjects.

The CKD–EPI equation was developed to estimate GFR more precisely, particularly when GFR levels were high.

It uses a two-slope spline to model the relationship between eGFR and serum creatinine.

In the validation data set, it demonstrated a tighter limit of agreement and outperformed the MDRD equation, which showed broader variability. CKD–EPI also showed less bias, especially at higher GFR levels.

CKD–EPI is also more accurate than MDRD and could replace it for routine clinical use.

However, the CKD–EPI samples have limited elderly and racial minority representation.