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Renal function estimates

Cockcroft-Gault creatinine clearance and the 2021 CKD-EPI eGFR, side by side in their own units. They are different quantities, so the units stay attached and a height de-indexes the eGFR into this patient's own millilitres per minute.

years
Sex
kg

This names the weight you entered. It does not convert it. Use the body weight calculator to compute an ideal or adjusted weight first.

The two scales differ by a factor of 88.4.

Creatinine unit
cm

With a height the eGFR is also de-indexed.

Enter an age, a weight and a serum creatinine to see both estimates.

The equation says only weight, and practice is inconsistent: ideal or adjusted body weight is often used instead of actual weight in obesity. This calculator uses the weight you enter and names it rather than substituting one.

Creatinine clearance in mL/min and eGFR in mL/min/1.73 m2 are different quantities: the second is indexed to a standard body surface area rather than this patient's. Which estimate a drug label was built on varies, so the dose adjustment belongs to that label and not to this arithmetic.

Formula

  • Cockcroft-Gault (mL/min) = (140 - age) x weight (kg) x 0.85 if female / (72 x creatinine mg/dL)
  • CKD-EPI 2021 (mL/min/1.73 m2) = 142 x min(SCr/K,1)^a x max(SCr/K,1)^-1.200 x 0.9938^age x 1.012 if female
  • K is 0.7 for females and 0.9 for males; a is -0.241 for females and -0.302 for males
  • Mosteller body surface area (m2) = square root of (height cm x weight kg / 3600)
  • De-indexed eGFR (mL/min) = eGFR (mL/min/1.73 m2) x body surface area / 1.73
  • Creatinine in micromoles per litre divided by 88.4 gives milligrams per decilitre

Source

  • Cockcroft-Gault (Cockcroft & Gault 1976) and the 2021 CKD-EPI creatinine equation as published by NIDDK and StatPearls; the de-indexing step for medication decisions per FDA and the National Kidney Foundation; Mosteller body surface area (StatPearls, NCBI Bookshelf NBK559005).

Clinical reference only. Verify independently; clinical judgment governs.