What is the Cockroft-Gault equation for determining renal function?

Updated: Jun 20, 2018
  • Author: Eleanor Lederer, MD, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Check serum levels of blood urea nitrogen (BUN) and creatinine to determine whether renal insufficiency is present. If such insufficiency is confirmed, check 24-hour urine for creatinine clearance or estimate the creatinine clearance using the Cockroft-Gault equation to assess whether the degree of renal insufficiency alone explains the hyperkalemia. The Cockroft-Gault equation is as follows:

(140 – age [y]) ´ weight (kg)/72 ´ serum creatinine (mg/dL)

For women, the result is multiplied by 0.8.

It must be kept in mind that because the serum creatinine level is dependent on muscle mass, a seemingly normal creatinine level in a geriatric or cirrhotic patient will actually indicate impaired renal function. Tools such as the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas are recommended for estimating glomerular filtration rate (GFR) in these patients. [1] The MDRD formula for estimating the GFR is as follows [60] :

186 ´ serum creatinine (mg/dL)−1.154 ´ age (y)−0.203 (´ 0.742 if female) (´ 1.210 if black)


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