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Anthropometric formulas

 

 

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

 

 

Serum Creatinine Adjustement for IDMS CREAT

 

If your laboratory utilizes the IDMS traceable creatinine, the serum creatinine must be adjusted in order to use older equations such as Cockroft and Gault:

 

Non-IDMS SrCr (mg/dL) = IDMS CREAT (mg/dL) x 1.065 + 0.067

 

 

Creatinine Clearance (CrCl) per Cockroft and Gault

 

The default method uses Lean Body Weight. The reason for this is, creatinine is a by-product of muscle metabolism, not fat. Therefore, excess weight, in the form of fat, does not significantly affect the production of creatinine

 

You may optionally choose to calculate with an Adjusted body weight:

 

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

 ABW = LBW + [0.3 x (WT-LBW)]

 where        

         WT = actual body weight in kg

         LBW = lean body weight in kg

 

*Obesity defined as BMI > 30.

 

 

2.   Calculate creatinine clearance (CrCl)

 CrCl Males = [ABW x (140 - Age)] / (SrCr x  72)

 CrCl Females = 85% of male value

 where        

         SrCr = the most recent serum creatinine in mg/dL

         ABW = adjusted body weight in kg

 

 

Note: For optional CrCl methods, please see the help topic Other Creatinine Clearance Methods.

 

 

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/SrCr) 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

 

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