Total body potassium and 24-hour creatinine excretion in healthy males.

Total body potassium may be predicted from height, weight, and age by TBKmmol = 30.83 Hcm + 18.05 Wkg - 11 (ageyr - 20) - 3034. This equation, based on measurements of 31 men, has been compared with others in the literature. Prediction of 24-hr creatinine (CR), excretion derived from 33 control adults whose excretion rates gave a coefficient of variation less than 13%, may be made from the equation: CRgm = 0.0143 Hcm + 0.00975 Wkg - 0.00734 (ageyr -20) -1.391. For 31 chronic schizophrenics, the corresponding equation CRgm = 0.0122 Hcm + 0.0145 Wkg - 1.611 contained no age correction. The relationship between CR and TBK is expressed by CRgm = 0.000403 TBKmmol + 0.278. Discussion of significance of these equations in the light of extensive literature suggests that about half of the error variance in predicting CR may be explained by the lack of suitable data on somatotype and much of the residual variance, including the day-to-day variation in CR, relate to factors altering basal O2 consumption. The predictors given should prove generally satisfactory for many metabolic and drug studies.