Erythrocyte Volume, Plasma Volume, and Lean Body Mass in Adult Men and Women

Erythrocyte volume, plasma volume, hematocrit, lean body mass (from total body water), skinfold thickness (at three sites), arm circumference, height, and weight were measured in 40 normal males, 38 normal females, and 12 obese females. From these data on the normal subjects, equations for estimating erythrocyte and plasma volumes were derived. Equations utilizing combined height-weight, surface area, height-weight-skinfold thickness, or lean body mass were found to be the most accurate for predicting erythrocyte and plasma volumes in normal and in obese subjects. The body:venous hematocrit ratio (BH:VH) and the variability of this ratio in our subjects were determined and discussed. Errors in indirect estimates of blood volumes based on this ratio are presented. Erythrocyte and plasma volume standards based on height-weight regression equations or surface area ratio equation are suggested for use in clinical laboratories. Tables and a nomogram based on these equations have been prepared and are available on request.