Jones Alan W
Department of Forensic Chemistry and Genetics, National Board of Forensic Medicine, and University Hospital, Linköping, Sweden.
Toxicol Rev. 2006;25(1):15-35. doi: 10.2165/00139709-200625010-00002.
This article concerns the use of urine as a biological specimen for determination of alcohol in clinical and forensic toxicology and discusses factors that might influence variability in the urine/blood concentration ratio of alcohol. A large number of human drinking experiments were conducted to determine the time course of urine-alcohol concentrations (UAC) in relation to blood-alcohol concentrations (BAC). The UAC and BAC curves were shifted in time and the BAC curve always began to decrease before the UAC started to decline. During the early absorption phase the UAC/BAC ratio was less than unity, whereas in the late absorption/distribution period the ratio was between 1.0-1.2. On reaching the post-absorptive phase, the UAC always exceeded BAC and UAC/BAC ratios averaged 1.3-1.4, increasing appreciably as BAC decreased towards zero. Alcohol-induced diuresis was most pronounced during the rising portion of the BAC curve and near to the peak value. After about 2 hours post-drinking, the production rate of urine diminished to the pre-drinking rate of about 0.5-1 mL/min. Drinking water during the post-absorptive phase of the alcohol curve produced dilute urine, as reflected in lower creatinine content and osmolality, although the concentration of ethanol remained unchanged. After subjects drank a moderate dose of ethanol (0.54-0.85 g/kg) about 2% of the dose was recoverable in the urine after 7 hours. Ethyl glucuronide, a minor metabolite of ethanol, was measured in urine samples from drunk drivers. The UAC/BAC ratio of ethanol in drunk drivers did not depend on the creatinine content of the urine and therefore the relative dilution of the specimens. When alcohol-free urine was spiked with glucose and infected with the yeast species Candida albicans, ethanol was produced by fermentation after approximately 24 hours storage at room temperature. This post-sampling synthesis of ethanol was prevented by sodium fluoride (1% weight by volume) in the urine tubes or by keeping the specimens in the cold (4 degrees C). The UAC and BAC were highly correlated (r > 0.95) in drunk drivers and in autopsy cases, although the residual standard deviations were appreciable. This speaks against attempting to estimate BAC indirectly from UAC in any individual case. The UAC/BAC ratio and the change in UAC between two successive voids can help to resolve whether a large amount of alcohol had recently been consumed. This information is useful to support or challenge allegations of drinking alcohol after driving, which has become known as the hip-flask defence.
本文涉及尿液作为临床和法医毒理学中酒精测定的生物样本的应用，并讨论了可能影响酒精尿液/血液浓度比变异性的因素。进行了大量人体饮酒实验，以确定尿液酒精浓度（UAC）相对于血液酒精浓度（BAC）的时间进程。UAC和BAC曲线在时间上发生偏移，并且BAC曲线总是在UAC开始下降之前就开始下降。在早期吸收阶段，UAC/BAC比值小于1，而在晚期吸收/分布阶段，该比值在1.0 - 1.2之间。进入吸收后阶段，UAC始终超过BAC，UAC/BAC比值平均为1.3 - 1.4，随着BAC降至零而显著增加。酒精诱导的利尿在BAC曲线上升部分和接近峰值时最为明显。饮酒后约2小时，尿液生成速率降至饮酒前约0.5 - 1 mL/分钟的速率。在酒精曲线的吸收后阶段饮水会产生稀释尿液，这反映在肌酐含量和渗透压较低，尽管乙醇浓度保持不变。受试者饮用适量乙醇（0.54 - 0.85 g/kg）后，约2%的剂量在7小时后可在尿液中回收。在酒驾司机的尿液样本中检测到乙醇的次要代谢产物乙基葡萄糖醛酸。酒驾司机尿液中乙醇的UAC/BAC比值不取决于尿液中的肌酐含量，因此也不取决于样本的相对稀释度。当无酒精尿液添加葡萄糖并感染白色念珠菌时，在室温下储存约24小时后通过发酵产生乙醇。尿液管中加入氟化钠（1%重量/体积）或在低温（4℃）下保存样本可防止采样后乙醇的合成。在酒驾司机和尸检案例中，UAC和BAC高度相关（r > 0.95），尽管剩余标准差较大。这表明在任何个别情况下都不应试图从UAC间接估计BAC。UAC/BAC比值以及两次连续排尿之间UAC的变化有助于判断近期是否饮用了大量酒精。这些信息对于支持或质疑酒后驾车的指控很有用，酒后驾车指控已被称为“小酒瓶抗辩”。
