RENAL FUNCTION ASSESSMENT FINAL SPRING
EXAMINATION (2025/2026) CHRONIC KIDNEY
DISEASE (CKD)
CLINICAL CALCULATION, INTERPRETATION AND APPLICATION
IN NURSING PRACTICE
MDRD (eGFR), COCKCROFT–GAULT (CREATININE CLEARANCE) METHODS
List the limitations of the modification diet of renal disease (MDRD) and Cockgraft-Gault
equations
The major limitation for both equations is that at glomerular filtration rates above 60, their
estimation is not accurate. The equation is much more accurate for stages II to V.
Cockgraft-Gault does not take into account ethnicity or nutritional status. The MDRD is
preferred because it has been extensively studied and takes into account other variables.
MDRD is limited in that it only accounts for 1 race (black). Other minority groups are not
accounted for and thus their GFR may not be truly representative.
**TAKE AWAY** Both are less accurate with GFR greater than 60.
List the Cockgraft-Gault equation
Calculated by the following:
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, (140-age) x lean body mass (kg) / serum creatinine (mg/dl) x 72. The equation is further
modified by multiplying the result by 0.85 for woman (as a way for accounting for the lower
body mass).
The Cockgraft-Gault equation is easily memorized and only requires one blood test to calculate,
the serum creatinine.
Limited by variances in the body mass (relies on serum creatinine for calculations). Can be over
or under estimated based on GFR.
It also loses accuracy in patients with amputated limbs, particularly the lower extremity
List the Modification Diet of Renal Disease equation
Calculated by using:
(Age) exp[-0.176] x (BUN [mg/dl]) exp[-0.170] x (Alb [g/dl]) exp[+0.318] x (0.762 if female0 x
(1.18 if black)
Complicated equation and shouldn't be memorized.
-Regarded as being more accurate method
-Widely studied and also accounts for nutrition and ethnicity
-Limitations include losing accuracy at GFR greater than 60 and lab errors
-Serum BUN and albumin required and if inaccurate or inconsistent, will be effected
-Limited by patients with unusual body mass as is seen with obese, malnourished and amputees
2|Page
EXAMINATION (2025/2026) CHRONIC KIDNEY
DISEASE (CKD)
CLINICAL CALCULATION, INTERPRETATION AND APPLICATION
IN NURSING PRACTICE
MDRD (eGFR), COCKCROFT–GAULT (CREATININE CLEARANCE) METHODS
List the limitations of the modification diet of renal disease (MDRD) and Cockgraft-Gault
equations
The major limitation for both equations is that at glomerular filtration rates above 60, their
estimation is not accurate. The equation is much more accurate for stages II to V.
Cockgraft-Gault does not take into account ethnicity or nutritional status. The MDRD is
preferred because it has been extensively studied and takes into account other variables.
MDRD is limited in that it only accounts for 1 race (black). Other minority groups are not
accounted for and thus their GFR may not be truly representative.
**TAKE AWAY** Both are less accurate with GFR greater than 60.
List the Cockgraft-Gault equation
Calculated by the following:
1|Page
, (140-age) x lean body mass (kg) / serum creatinine (mg/dl) x 72. The equation is further
modified by multiplying the result by 0.85 for woman (as a way for accounting for the lower
body mass).
The Cockgraft-Gault equation is easily memorized and only requires one blood test to calculate,
the serum creatinine.
Limited by variances in the body mass (relies on serum creatinine for calculations). Can be over
or under estimated based on GFR.
It also loses accuracy in patients with amputated limbs, particularly the lower extremity
List the Modification Diet of Renal Disease equation
Calculated by using:
(Age) exp[-0.176] x (BUN [mg/dl]) exp[-0.170] x (Alb [g/dl]) exp[+0.318] x (0.762 if female0 x
(1.18 if black)
Complicated equation and shouldn't be memorized.
-Regarded as being more accurate method
-Widely studied and also accounts for nutrition and ethnicity
-Limitations include losing accuracy at GFR greater than 60 and lab errors
-Serum BUN and albumin required and if inaccurate or inconsistent, will be effected
-Limited by patients with unusual body mass as is seen with obese, malnourished and amputees
2|Page
