FATTY-ACID ETHYL-ESTERS IN THE BLOOD AS MARKERS FOR ETHANOL INTAKE

Objective.-To determine the clinical utility of farcy acid ethyl eater s (FAEEs) in the blood as a short-term confirmatory marker for ethanol intake and a longer-term marker for ethanol intake after ethanol is n o longer detectable. Design.-Single-center controlled clinical trial a nd a blinded comparison involving 48 blood samples that were positive, negative, or equivocal for blood ethanol. Participants.-Seven healthy subjects (4 men and 3 women, aged 21 to 23 years) participated in the clinical trial. Blood samples from participants for the blinded compa rison portion of the study were numbered from 1 to 48 and not identifi ed by name. Intervention.-The 7 healthy subjects ingested a known amou nt of ethanol at a fixed rate. The concentration of FAEEs in the blood alter ethanol intake was determined for a period of up to 24 hours. T here was no intervention in the blinded comparison study. Main Outcome Measures.-In the clinical trial, a pharmacokinetic analysis of FAEE c oncentration in the blood after ethanol intake was completed for 7 ind ividuals whose blood ethanol level was elevated from 25 to 35 mmol/L. In the blinded comparison, the 48 blood samples that were positive, ne gative, or equivocal for blood ethanol were analyzed for FAEE concentr ation. Results.-In the clinical trial, the disappearance of FAEEs from the blood followed a decay curve that initially resembled the decay c urve for blood ethanol. However, because of a very slow secondary elim ination phase, the FAEEs were found to persist in the blood for at lea st 24 hours after ethanol intake was completed, In the blinded compari son, all 20 samples that were positive for ethanol were positive for F AEEs, 7 of 7 samples equivocal for ethanol were positive for FAEEs, an d 21 of 21 negative samples for ethanol were negative for FAEEs. Concl usions.-Serum concentration of FAEEs can serve as an excellent shortte rm confirmatory test for ethanol intake as well as a longer-term marke r of ethanol ingestion. Measurement of FAEEs in the blood may be a mor e sensitive indicator of ethanol ingestion than the measurement of blo od ethanol.