Comparison of Plasma, Serum, and Whole Blood Ethanol Concentrations

Abstract

The differences in ethanol concentrations, as measured by direct injection gas chromatography, among plasma, serum, and whole blood from living human subjects are examined. The samples containing serum and the corresponding ones containing whole blood arrived at the laboratory as part of the same submission. The ratio of the concentration of ethanol in serum to that in plasma is 1.00 +/- 0.01:1 with a range of 0.98:1 to 1.04:1. The serum/whole blood ratio and plasma/whole blood ratio are both 1.12 +/- 0.02:1. The former has a range of 1.09:1 to 1.18:1 and the latter ranges from 1.09:1 to 1.17:1.

A study of ethyl glucuronide in post-mortem blood as a marker of ante-mortem ingestion of alcohol

“…For instance, the concentration of tetrahydrocannabinol has been found to be almost twice as high when measured in serum rather than in whole blood (141). This ratio is also well known for ethanol (142)(143)(144)(145), but no such data existed on EtG and EtS.…”

Alcohol Calculations in Emergency and Forensic Medicine

“…Early studies reported the serum: whole blood alcohol ratio to be about 1.1 to 1.2 [16], with an accepted average of 1.18 [17,18]. A hospital serum alcohol can be reasonably and quickly converted to a whole blood equivalent by dividing the serum concentration by 1.18 or multiplying the serum value by the reciprocal (e.g., serum x .85).…”

Blood alcohol concentration for monitoring ethanol treatment to prevent alcohol withdrawal in the intensive care unit

“…Considering the different techniques used to measure ethanol levels, the determination of BAC in whole blood by gas chromatography is the most specific method and considered the reference method for alcohol determination in forensic settings [11]. However, the alcohol dehydrogenase spectrophotometric method is commonly used for measuring ethanol in biological fluids [12].…”

“…However, the alcohol dehydrogenase spectrophotometric method is commonly used for measuring ethanol in biological fluids [12]. This may account for differences between forensic journals and ICU references [4,11]. In addition, venous blood alcohol levels are usually determined in forensic settings [11] and arterial ethanol levels in ICUs [4].…”

“…This may account for differences between forensic journals and ICU references [4,11]. In addition, venous blood alcohol levels are usually determined in forensic settings [11] and arterial ethanol levels in ICUs [4]. One study found that differences between arterial (aBAC) and venous BAC (vBAC) exist during the loading phase, but disappear rapidly when the administration of ethanol terminates [13].…”