Segal et al estimated extracellular water for an adult male from bioelectrical impedance, height and weight. The authors are from Mount Sinai Medical School and St. Luke's-Roosevelt Hospital in New York City.


Patient population: adult



(1) height in cm

(2) weight in kilograms

(3) resistance in ohms measured using bioelectrical impedance (at 100 kHz)


total body water in liters =

= (0.284 * (((height in cm)^2) / (ohms))) + (0.11196 * (weight in kilograms)) - 6.1153


intracellular water in liters=

= (total body water in liters) - (extracellular water in liters)



• The height squared divided by the resistance is called the impedance index.



• The R-squared was 0.930 and standard error of the estimate (SEE) 1.94.


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