The calculation of blood ethanol concentrations in males and females

Abstract

In German-speaking countries, blood ethanol concentrations (BECs) are usually calculated using Widmark's equation. The distribution factor r of this equation is a correction factor needed to obtain a reduced body mass and corresponds to the ratio of total body water and blood water content. To enhance the reliability of Widmark's model equation, the body weight, body height, blood water content and total body water of 256 women and 273 men were measured. 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 developed by multiple regression analysis which allow the determination of the individual, more realistic distribution factors rFI (for females) and rMI (for males) even when only body height and body weight are known. Drinking experiments revealed a clearly higher congruence of calculated and measured blood ethanol concentrations when rFI or rMI were used instead of rigid distribution factors, i.e. 0.6 for women and 0.7 for men with or without the assumption of a 10% so-called resorption deficit. Additionally, Widmark's equation in combination with rFI or rMI allows a more accurate prediction of blood ethanol concentrations than the equations of Watson and Ulrich.

Widmark factors for local Chinese in Hong Kong

“…It is noted that even in the studies for Caucasians, the height variable did not help explain much variability of factor values after the weight variable was accounted for [26]. In fact, a discrepancy was noted amongst the factor r 0 calculated in our study and the one generated from the equations suggested by Seidel et al [4] for both genders under empty stomach condition (F: P-value = 0.09 and M: P-value < 0.001). The factors, r 0, generated by the latter equations with the consideration of height and weight of participants only are 0.76 and 0.71 for males and females, respectively.…”

“…A general form of the Widmark formula is A = ((C Â W Â r 0 )/100) where A is the weight of the alcohol consumed (g), C is the blood alcohol concentration (BAC) (mg/100 mL), W is the body weight of the subject (Kg), and r 0 is the Widmark factor which relates to the total body water and body weight [4,5]. The mean Widmark factors reported were 0.68 and 0.55 for Caucasian male and female, respectively, [1] with the measured blood alcohol concentrations (BAC) in the units of weight by weight (mg/100 g).…”

A fatal case of pure ethanol ingestion

“…However, even if some adjustments are made utilizing other methods, the calculated amount would not be greatly different for interpreting the current case, i.e. 385 ml instead of 325 ml utilizing Seidl's equation [12].…”

Alcohol influences the use of decisional support

“…Each participant was randomly administered either a 'high' dose of alcohol or a 'low' dose of alcohol on different days, based on an equation designed to have them reach either a blood alcohol level of 0.08% BAC or a 0.02% BAC (Seidl et al 2000), drinking 37 proof Vodka, which was made up to 1 L in volume with orange juice.…”