Urine/blood ratios of ethanol in deaths attributed to acute alcohol poisoning and chronic alcoholism

Abstract

The concentrations of ethanol were determined in femoral venous blood (BAC) and urine (UAC) and the UAC/BAC ratios were evaluated for a large case series of forensic autopsies in which the primary cause of death was either acute alcohol poisoning ( N=628) or chronic alcoholism ( N=647). In alcohol poisoning deaths both UAC and BAC were higher by about 2 g/l compared with chronic alcoholism deaths. In acute alcohol poisoning deaths the minimum BAC was 0.74 g/l and the distribution of UAC/BAC ratios agreed well with the shape of a Gaussian curve with mean±standard deviation (S.D.) and median (2.5th and 97.5th centiles) of 1.18±0.182 and 1.18 (0.87 and 1.53), respectively. In alcoholism deaths, when the BAC was above 0.74 g/l ( N=457) the mean±S.D. and median (2.5th and 97.5th centiles) UAC/BAC ratios were 1.30±0.29 and 1.26 (0.87 and 2.1), respectively. When the BAC was below 0.74 g/l ( N=190), the mean and median UAC/BAC ratios were considerably higher, being 2.24 and 1.58, respectively. BAC and UAC were highly correlated in acute alcohol poisoning deaths ( r=0.84, residual S.D.=0.47 g/l) and in chronic alcoholism deaths ( r=0.95, residual S.D.=0.41 g/l). For both causes of death ( N=1275), the correlation between BAC and UAC was r=0.95 and the residual S.D. was 0.46 g/l. The lower UAC/BAC ratio observed in acute alcohol poisoning deaths (mean and median 1.18:1) suggests that these individuals died before absorption and distribution of ethanol in all body fluids were complete. The higher UAC/BAC ratio in chronic alcoholism (median 1.30:1) is closer to the value expected for complete absorption and distribution of ethanol in all body fluids.