Stability of Ethanol in Stored Blood: A Validation Study for Blood Alcohol Determination in Victims of Road Traffic Accidents in the Ivory Coast

Abstract

Background: In the Ivory Coast, only the National Laboratory of Toxicology is qualified to complete blood-alcohol testing in road traffic victims or drunk-driving victims. However, there is no legal or existing standardized operational procedure for blood storage and transportation from the emergency units to the National Laboratory of Toxicology.
Objectives: The objectives of this study were to monitor the efficacy of the cold chain from the victim’s bed to the laboratory of toxicology and to assess the stability of whole blood samples with known concentration of ethanol during transportation, storage and pre-analytical phase.
Design and Methods: The cold chain was composed of a cool box, a refrigerator (from +2°C to +8°C) and a freezer (?18°C). Temperature was monitored for each cold device using a digital thermometer. Deviations from targeted or expected temperatures were assessed using control cards. Ethanol concentrations were determined by CPG-FID at baseline, after 24, 48, 72, 120 h and day 15 for blood controls A) stored at +5°C, B) left at room temperature, C) after 3 freeze and thaw cycles and D) after extraction. Differences between ethanol levels at baseline and at various times were tested by the test of Student and ANOVA.
Results: At each stage of the storage and transportation process, temperature in cool devices remained in the targeted range. We found a statistically significant decrease of ethanol in refrigerated blood sample after 15 days of storage. Ethanol loss was significant at ambient temperature after 5 days and after 3 freeze-thaw cycles. In the supernatant, ethanol was stable up to 72 h.
Conclusion: Regarding our working conditions and storing procedures, alcohol concentration can be accurately measured in ER patients’ blood in a frame time of 5 days, provided the samples are refrigerated.