Stability of Ethanol in Blood and Urine Samples

Stability of Ethanol in Blood and Urine Samples The changes of ethanol concentrations in whole blood and urine samples were analyzed depending on temperatures and duration of storage. The aim of the study was to establish standards for the Institute laboratory. Samples of whole blood and urine, taken from drivers with excessive alcohol concentrations (6 groups, 15 samples per each), were analyzed upon delivery and then after storage during different time intervals and at different temperatures. The results showed that alcohol concentrations were significantly reduced with the increase of temperature and prolongation of storage. Only the whole blood samples stored for up to one month at -20 °C did not show significant changes. Room temperature storage of samples is the least suitable way of keeping them, independently of the duration of storage. Urines are not less reliable samples than blood. There are no ethanol differences between blood samples with and without sodium fluoride.