Creatinine Clearance Calculator (Cockcroft-Gault) Formula

Understand the math behind the creatinine clearance calculator (cockcroft-gault). Each variable explained with a worked example.

Use the Creatinine Clearance Calculator (Cockcroft-Gault)

Formulas Used

Creatinine Clearance

crcl = ((140 - age) * weight_kg) / (72 * serum_creatinine) * gender_factor

GFR Estimate

kidney_stage = ((140 - age) * weight_kg) / (72 * serum_creatinine) * gender_factor

Variables

VariableDescriptionDefault
ageAge(years)50
weight_kgWeight(kg)80
serum_creatinineSerum Creatinine(mg/dL)1
gender_factorGender1

How It Works

Cockcroft-Gault Equation

CrCl = [(140 - Age) x Weight(kg)] / [72 x Serum Creatinine] x (0.85 if female)

This equation estimates creatinine clearance as a proxy for glomerular filtration rate (GFR).

Kidney Function Stages

| CrCl (mL/min) | Stage | |---|---| | >90 | Normal | | 60-89 | Mild decrease | | 30-59 | Moderate decrease | | 15-29 | Severe decrease | | <15 | Kidney failure |

Worked Example

A 50-year-old male, 80 kg, serum creatinine 1.0 mg/dL.

age = 50weight_kg = 80serum_creatinine = 1gender_factor = 1
  1. 01CrCl = (140 - 50) x 80 / (72 x 1.0)
  2. 02= 90 x 80 / 72
  3. 03= 7200 / 72 = 100 mL/min (Normal)

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