When calculating creatinine clearance using the MDRD equation, which of the following factors are considered?

When calculating creatinine clearance using the MDRD equation, which of the following factors are considered?

• A. Verification that the patient has been fasting
• B. Identification of ethnicity
• C. Body mass
• D. Time of day of blood collection

Answer: (B)

The main idea here is how the MDRD equation estimates GFR. This equation uses serum creatinine along with a few demographic factors to tailor the estimate. Specifically, it includes age, sex, and race/ethnicity as factors. The race/ethnicity adjustment accounts for differences in baseline creatinine production linked to muscle mass and other population characteristics, which is why identifying ethnicity is incorporated into the calculation. Fasting status, body mass, and the time of day the blood is drawn do not enter into the MDRD formula. Fasting generally doesn’t meaningfully change serum creatinine, body mass isn’t a factor in this equation, and the time of collection isn’t used because creatinine production is relatively stable and the formula relies on the included variables to adjust for differences in creatinine generation.

The main idea here is how the MDRD equation estimates GFR. This equation uses serum creatinine along with a few demographic factors to tailor the estimate. Specifically, it includes age, sex, and race/ethnicity as factors. The race/ethnicity adjustment accounts for differences in baseline creatinine production linked to muscle mass and other population characteristics, which is why identifying ethnicity is incorporated into the calculation.

Fasting status, body mass, and the time of day the blood is drawn do not enter into the MDRD formula. Fasting generally doesn’t meaningfully change serum creatinine, body mass isn’t a factor in this equation, and the time of collection isn’t used because creatinine production is relatively stable and the formula relies on the included variables to adjust for differences in creatinine generation.