Anthropometric formulas

See also

 

Top  Previous  Next

 

Adults

 

Lean body weight (LBW)

Devine equation:

LBW (Males) = 50 + [ 2.3 x  (60 - Height in inches) ]

LBW (Females) = 45.5 +  [ 2.3 x  (60 - Height in inches) ]

 

Hume equation:

LBW (Males) = (0.3281 x Weight in kg) + (0.33939 x Height in cm) - 29.5336

LBW (Females) = (0.29569 x Weight in kg) + (0.41813 x Height in cm) - 43.2933

 

The Devine method is the default result. For short stature patients (less than 60 inches), the Hume method is utilized when its result is less than baseline LBW (50kg for males, 45.5kg for females) and greater than Devine.

 

Please note that neither of these method is valid in amputees.

 

Body surface area (BSA)

Mosteller equation:

BSA  = Square root of  (HT X WT) / 3600

where:

 HT = height in centimeters

 WT = weight in kilograms

 

Creatinine Clearance (CrCl) per Jelliffe Multistep Method

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 (SrCr1-SrCr2)] / D

where        

 LBW = lean body weight in kilograms

SrCr1= the latest serum creatinine

SrCr2= 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 in mg/dL

BSA = Body surface area

 

Creatinine Clearance (CrCl) per Cockroft and Gault

1.        Calculate body weight adjusted for obesity* (ABW)

 ABW = LBW + [0.3 x (WT-LBW)]

 where

         WT = actual body weight

         LBW = lean body weight

 

*Obesity defined as BMI > 30..

 

2.        Calculate creatinine clearance (CrCl)

 

CrCl Males = [Wt x (140 - Age)] / (SCr x  72)

CrCl Females = 85% of male value

where        

 SCr is the most recent serum creatinine in mg/dL

 Wt = LBW in normal weight patients or ABW in obese patients

 

Optional CrCl methods

Cockcroft and Gault TBW

This variation of the C&G equation uses Total Body Weight instead of Ideal Body Weight.

Be aware however, that this tends to over-estimate CrCl in larger patients.

CrCl Males = [TBW x (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 is substantially different from average.

This is also the method used when "Adjust CL to IBW" is checked.

CrCl Males = (140 - Age) / SrCr

CrCl Females = 85% of male value

 

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)) / SrCr

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{SrCr} )  - ( 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 Ht2 )] }  /  (51 x SrCr)

CrCl Females        = { ( 146 - Age ) x [ ( 0.287 x Wt)  + (9.74 x Ht2 )] }  /  (60 x SrCr)

 

 

Pediatrics

 

Lean body weight (LBW)

Traub equation:

LBW = (HT2 x  1.65)/1000

 where        

         HT = height in centimeters

 

Body surface area (BSA)

Haycock equation:

BSA  =  0.024265 x HT 0.3964 x WT 0.5378

 where        

         HT = height in centimeters

         WT = weight in kilograms

 

Creatinine Clearance (CrCl) per Schwartz

 

CrCl =  (k x Ht/Scr) x  (1.73/BSA)

 where

         HT = height in centimeters

         SrCr = the most recent serum creatinine in mg/dL

         k = 0.33 if weight < 2.5 kg

         k = 0.45 if age <1 year

         k = 0.55 if age 1-12 years

 

 

Copyright 1999-2013 by RxKinetics. All rights reserved.