The calculation of blood ethanol concentrations in males and females

Ln German-speaking countries, blood ethanol concentrations (BECs) are usual ly calculated using Widmark's equation. The distribution factor r of this e quation is a correction factor needed to obtain a reduced body mass and cor responds to the ratio of total body water and blood water content. To enhan ce the reliability of Widmark's model equation, the body weight, body heigh t, blood water content and total body water of 256 women and 273 men were m easured. The ratio of body water to blood water ranged from 0.44 to 0.80 in women and from 0.60 to 0.87 in men. For both sexes equations were develope d by multiple regression analysis which allow the determination of the indi vidual, more realistic distribution factors r(FI) (for females) and r, (for males) even when only body height and body weight are known. Drinking expe riments revealed a clearly higher congruence of calculated and measured blo od ethanol concentrations when r, or r(MI) were used instead of rigid distr ibution factors, i.e. 0.6 for women and 0.7 for men with or without the ass umption of a 10% so-called resorption deficit. Additionally, Widmark's equa tion in combination with rFI Or TMI allows a more accurate prediction of bl ood ethanol concentrations than the equations of Watson and Ulrich.