Finn et al determined the intracellular potassium concentration based on total body potassium, serum potassium and body water. The authors are from the Auckland Hospital in New Zealand.



(1) serum potassium in mmol/L

(2) total body potassium (determined by shadow shield counting of gamma emission from K-40, a naturally occurring isotope of potassium) in mmol

(3) total body water in liters (see Chapter 02).

(4) extracellular water in liters (see Chapter 02)


intracellular water in liters =

= (total body water) - (extracellular water)


extracellular potassium in mmol =

= (serum potassium in mmol/L) * (extracellular water in liters)


intracellular potassium in mmol =

= (total body potassium) - (extracellular potassium)


intracellular potassium concentration in mmol/L =

= (intracellular potassium in mmol) / (intracellular water in liters)


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