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Examples: Cockroft-Gault Calculation

Examples: Cockroft-Gault Calculation
So let’s look at a couple of examples for Cockroft-Gault Calculation. This is a male patient, age 40, gross body weight 70 kg and the serum creatinine 1 milligram percent. If height is not available, then use gross weight. And we would obtain a creatinine clearance value of ninety seven point two milliliters per minute. For the same subject, if the height is available one hundred seventy centimeters. And we can calculate ideal body weight which is equal to sixty six point two kilogram. And on that basis, creatinine clearance is ninety one point nine milliliters per minute. For the same subject again, if we normalize the creatinine clearance value to 1.73 meters square.
Of course we have to calculate body surface area first by the DuBois equation. And creatinine clearance becomes eighty seven point eight milliliters per minute. And those three values are fairly consistent with each other. Because this male subject is very close to Mr. standard. Another example of Cockroft-Gault calculation. This is the female patient, age 40, body weight 60 kg and the serum creatinine one milligram percent. If height is not available, use gross weight. Then creatinine clearance would be 70.8 milliliters per minute. However, for this same subject, if height is available at 155 cm, we first calculate the ideal body weight. Which turn out to be forty eight point two kg and the creatinine clearance is 56.8 milliliters per minute.
Again for the same subject, we normalize the creatinine clearance to 1.73 meters square. We compute body surface area first by DuBois equation. And the creatinine clearance turn out to be 62.9 milliliters per minute per 1.73 meters square. Now this revalues is somewhat different. The reason is this female subject is kind of heavy for her weight and weight does affect Cockroft estimation of creatinine clearance.

Continuing from the previous step, Prof. Lee gives two examples to illustrate Cockroft-Gault Calculation this time.

The first case is a male patient. We need to know how to calculate the creatinine clearance correctly based on the gross weight, known height, and BSA.

Following that, we compute body surface area by DuBois equation.

The second case is a female patient. We have to notice her weight, which will impact the creatinine clearance we are trying to get.

Below is an exercise adapted from the video, please try it on your own, and share your answer.

Female, age = 50, BW=60 Kg, Ccr=1 mg/dL, Height = 155 cm, what is her Clcr?

If you have any questions, please leave them below.

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Pharmacokinetics: Drug Dosing in Renal Disease

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