Levey et al developed equations for estimating the glomerular filtration rate (GFR) from creatinine and other serum measures. The authors are from the Modification of Diet in Renal Disease (MDRD) Study Group.
Patient population: adults
Parameters for the equations:
(1) plasma creatinine in mg/dL
(2) age of the patient in years
(3) gender
(4) race
(5) serum urea nitrogen in mg/dL
(6) serum albumin in g/dL
(7) urine urea nitrogen (UUN) in grams per day (g/d)
Equation Using Serum Values Only
|
Parameters
|
Findings
|
Points
|
|
gender
|
female
|
0.762
|
|
|
male
|
1
|
|
race
|
African-American
|
1.180
|
|
|
other
|
1
|
where:
• "Other race" definitely includes Caucasians. I am not sure how well other races are represented.
GFR in mL per min per 1.73 square meters BSA =
= 170 * ((plasma creatinine in mg/dL)^(-0.999)) * ((age of the patient in years)^(-0.176)) * (gender points) * (racial points) * ((serum urea nitrogen)^(-0.170)) * ((serum albumin)^(0.318))
Equation Using Serum and Urine Values
|
Parameters
|
Findings
|
Points
|
|
gender
|
female
|
0.822
|
|
|
male
|
1
|
|
race
|
African-American
|
1.178
|
|
|
other
|
1
|
GFR in mL per min per 1.73 square meters BSA =
= 198 * ((plasma creatinine in mg/dL)^(-0.858)) * ((age of the patient in years)^(-0.167)) * (gender points) * (racial points) * ((serum urea nitrogen)^(-0.293)) * ((urine urea nitrogen)^(0.249))
