﻿ Other Creatinine Clearance Methods
 Other Creatinine Clearance Methods   Click the "Other" button on the Patient data tab to select from alternate creatinine clearance methods.   Select the calculation method, then "Copy" to transfer the value to the patient data tab.   Click "Cancel" to close the window without copying the value to the patient data tab.   Cockcroft and Gault TBW This variation of the C&G equation uses Total Body Weight instead of Adjusted Body Weight.  Be aware however, that this tends to over-estimate CrCl in larger patients. CrCl Males = TBW(140 - Age) / (SCr x  72) CrCl Females = 85% of male value     Cockcroft and Gault Normalized Removes weight from the C&G equation.  Some find this variation useful in patients whose body size differs substantially from average. CrCl Males = (140 - Age) / SCr CrCl Females = 85% of male value     Jelliffe Multi-step 1.   Estimate urinary creatinine excretion rate E (males) = LBW x (29.305 -[0.203 x (age)]) E (females) = LBW x (25.3 -[0.18 x (age)])   2.   Correct for rising serum creatinine E = E - [4 x LBW x (SCr1-SCr2)] / D where LBW = lean body weight in kilograms  Scr1= the latest serum creatinine  Scr2= the earlier serum creatinine  D = the number of days between   3.   Calculate corrected creatinine clearance (CrCl)  CrCl/1.73 m2 =  (E * 0.12) / (SrCr * BSA)  where SrCr is the most recent serum creatinine     Jelliffe 1973 Weight is not used in this equation either, therefore, some find this method useful in patients whose body size is substantially different from average: CrCl Males = 98 - (0.8 x (Age-20)) / Scr CrCl Females = 90% of male value     MDRD (abbreviated) Derived from a large study of patients with a wide range of kidney function.  Some feel this is a more accurate GFR method overall. GFR Males = exp[ 5.228 - ( 1.154 x  log{SCr} )  - ( 0.203  x  log{Age} ) GFR Female = 74.2% of male value For African Americans multiply by 1.21   It is important to note that MDRD calculates GFR which does not directly correlate to CrCl   Salazar and Corcoran Derived from a study of obese patients.  Some recommend this method for obese patients instead of the standard equations. CrCl Males  =  { ( 137 - Age ) x [ ( 0.285 x Wt)  + (12.1 x Ht^2 )] }  /  (51 x SCr) CrCl Females  = { ( 146 - Age ) x [ ( 0.287 x Wt)  + (9.74 x Ht^2 )] }  /  (60 x SCr)   References