The Cockcroft-Gault equation for estimating GFR incorporates which patient parameters?

• A. Age, weight, gender, and serum creatinine
• B. Height, hair color, and weight
• C. Age only
• D. Serum potassium and calcium

Answer: (A)

The main idea here is that the Cockcroft-Gault formula estimates creatinine clearance, which is a proxy for GFR, using patient-specific factors that influence creatinine production and clearance. Specifically, it uses age, body weight, sex (gender), and serum creatinine because creatinine comes from muscle metabolism and its production varies with muscle mass. Age and weight help approximate how much muscle mass a person has, while sex accounts for typical differences in muscle mass between males and females. Serum creatinine reflects how well the kidneys are filtering. Putting these together allows the equation to estimate how quickly creatinine is cleared from the blood, which relates to GFR.

Height, hair color, and similar attributes aren’t part of the calculation because they don’t directly influence creatinine production or clearance in the way age, weight, and sex do. Relying on age alone would ignore body size and muscle mass; using serum potassium and calcium doesn’t inform kidney filtration in this formula.