Description

The total body nitrogen (TBN) can be used as a measure of a patient's nutritional status and to monitor conditions affecting nitrogen metabolism. Ellis et al published several equations for estimating the total body nitrogen from body measurements. The authors are from Brookhaven National Laboratory in New York.


 

Measurement of total body nitrogen: by prompt gamma neutron activation analysis

 

Subjects: adults (20 to 80 years), including healthy, cancer and obese individuals.

 

Estimate from Height, Body Weight, Age and Sex

 

total body nitrogen in grams for males =

= (7.30 * (body height in cm)) + (5.41 * (body weight in kilograms)) – (7.11 * (age in years)) + 423.3

 

 

total body nitrogen in grams for females =

= (14.94 * (body height in cm)) - (1.60 * (body weight in kilograms)) – (5.30 * (age in years)) – 785.3

 

Estimate from Height, Age and Sex

 

total body nitrogen in grams for males =

= (13.41 * (body height in cm)) – (6.46 * (age in years)) – 251.8

 

total body nitrogen in grams for females =

= (14.16 * (body height in cm)) – (5.11 * (age in years)) – 756.6

 

Estimate from Total Body Potassium and Sex

 

total body nitrogen in grams for males =

= (10.15 * (total body potassium in grams)) + 405.6

 

total body nitrogen in grams for females =

= (12.95 * (total body potassium in grams)) + 151.7

 


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