Ärztegesundheit: Die Bedeutung von Phosphatidylethanol als Bestätigungstest

Einleitung: Whereas urinary ethyl glucuronide (EtG) levels above 1000 ng/ml reflect with a high probability ethanol consumption, levels below this cutoff are difficult to interpret since both extraneous (non-beverage) ethanol exposure, recent drinking and more distant high ethanol intake (several days ago) might yield similar results. This might be of particular relevance in medico-legal cases. To overcome this dilemma phosphatidylethanol (PEth) might be a promising marker, since blood PEth is only positive following significant alcohol use. The aim of our study was therefore to employ PEth as a marker to differentiate between the different conditions.

Methode: Subjects included were 252 participants in monitoring with the Alabama Physician Health Program. All subjects testing positive for EtG and/or ethyl sulfate (EtS) who denied drinking after routine supportive confrontation were subject to information about PEth testing. If they still denied drinking, PEth testing was performed and the result communicated. EtG, EtS and PEth testing was performed in a commercial laboratory using LC-MS/MS methods.

Diskussion/Ergebnisse: Of a total of 18 subjects tested positive for EtG and/or EtS, 10 denied drinking. Out of the 7 who denied drinking after PEth explanation, in 5 cases their claim was supported by a negative PEth result. In 2 cases a positive PEth result was in contrast to their claim.

Schlussfolgerung: PEth results in combination with previous low positive EtG/EtS results allow differentiating between innocent/extraneous exposure and drinking. Negative PEth testing following low positive EtG/EtS results helps to further elucidate the findings and support the claim of the patient of recent alcohol abstinence. Positive PEth testing following positive EtG/EtS results confirms recent drinking.