eGFR calculator

Serum creatinine Unit µmol/l mg/dl

Patient age

Sex female male

Ethnicity not black black

Urea mmol/l

Patient weight Unit kg st / lb

stone lb

Patient height Unit cm ft / in

ft in

Estimated GFR

Schwartz bedside {{schwarzGFR | number:1}} ml/min/1.73m²

CKD EPI formula {{ckdEpiGFR | number:1}} ml/min/1.73m²

Abbreviated MDRD {{mdrd4v | number:1}} ml/min/1.73m²

Nankivell formula {{nankivell | number:1}} ml/min²

Walser formula {{walser | number:1}} ml/min/3m²

Estimated creatinine clearance

Cockcroft-Gault formula {{cockcroftGault | number:1}} ml/min

Cockcroft-Gault (IBW) {{cockcroftGaultIBW | number:1}} ml/min

Anthropometrics

Ideal body weight {{ibw | number:1}} kg

Body surface area {{bsa | number:2}} m²

Notes

Glomerular filtration rate can only be determined accurately by direct measurement of renal clearance of markers such as inulin, ⁵¹Cr-EDTA, ¹²⁵I-iothalamate or iohexol, but GFR can be estimated from serum creatinine using a number of formulae. There is no perfect formula for all levels of renal function, and all formulae can be inaccurate if renal function is unstable, at extremes of BMI, in pregnancy, muscle wasting or gross oedema.

The CKD-EPI and abbreviated MDRD formulae are the ones most commonly used for adults, and are both based on large numbers of patients with direct GFR measurement and standardised serum creatinine measurements using isotope dilution mass spectrometry. The CKD-EPI formula is more accurate for patients with GFR greater than 60 ml/min. The MDRD formula was updated in 2005, and this later revision is used here. The CKD-EPI formula was recommended for estimation of GFR in adults in NICE Clinical Guideline 128 (2014). In the USA, the MDRD formula was recommended in NKF-KDOQI 2002, and the CKD-EPI formula recommended by KDIGO 2013. Both produce an estimate of GFR for a patient with body surface area of 1.73m²

The bedside Schwartz formula is more accurate in children, and recommended for GFR estimation in patients under 19 by the National Kidney Federation and National Kidney Disease Education Program in the USA.

The Nankivell and Walser formulae are less commonly used. The Nankivell formula is the only eGFR formula derived entirely from renal transplant patients, but included patients with unstable GFR. The Nankivell formula includes weight and height so approximates an absolute GFR. The Walser formula produces a result standardised to a height² of 3m².

The Cockcroft-Gault equation estimates creatinine clearance rather than GFR and tends to overestimate actual GFR. If patient height is specified, the result is given here for both actual weight and ideal body weight. It is still widely used for renal drug dosing, although the National Kidney Federation in the USA recommend CKD-EPI or MDRD instead.

Results from online eGFR calculators may vary due rounding errors. This calculator converts creatinine units as 1.00 mg/dl being equal to 88.42 µmol/l

Links

• Renal Association guidance on eGFR
• NICE CG128: chronic kidney disease in adults
• NIDDK (NIH) guidelines on eGFR
• NKF guidance on eGFR

References

Mariat C, Maillard N, et al. Estimated glomerular filtration rate as an end point in kidney transplant trial: where do we stand? Nephrol Dial Transplant 2008; 23:33-38 Santos J, Martins LS. Estimated glomerular filtration rate in kidney transplantation: Still searching for the best marker. World J Nephrol 2015; 4(3):345-353

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