Total body potassium in normal children

Abstract

Normative data for total body potassium on 462 children (232 boys and 230 girls) are presented. The regression of total body potassium on weight can be described as a straight line for males (grams K = 4.32 +2.12 X weight) and two significantly different lines for females (grams K = -1.50 + 2.32 X weight for weight ≤30 kg, and grams K = 34.90 + 1.11 X weight for weight > 30 kg), with less potassium per kilogram for females weighing more than 30 kg. No sex-related difference is found between 12 and 30 kg. When the regression of total body potassium on height is examined, it is found that a logarithmic transformation of potassium values results in a similar pattern, with no sex-related differences between 100 and 135 cm and less potassium per centimeter in females over this height. For males, log K in grams = 1.761 + 0.0182 X cm of height; and for females, log K in grams = 1.595 + 0.01942 X cm for height ≤135 cm, and log K in grams = 2.574 + 0.01215 X cm for height > 135 cm. The logarithmic transformation of K versus height is proposed as a standard because it reflects changes in slope associated with known physiologic and endocrinologic changes occurring with puberty and may be more sensitive than weight in predicting abnormal values in individual patients. © 1972 International Pediatric Research Foundation, Inc.