The Drug and Alcohol Testing Blog

Phosphatidylethanol and CDT: the differences with these blood tests

Written by Lolita Tsanaclis | Nov 30, 2021

Doctors can use several biochemical measurements to objectively assess patients' current or past alcohol use. These include the alcohol biomarkers Carbohydrate-deficient transferrin (CDT) and Phosphatidylethanol (PEth).

CDT is a widely tested biomarker that can be used to assess chronic alcohol intake of more than 60 g ethanol/d, which is used in different settings for routine detection of heavy alcohol consumption and follow-up of treatment.

PEth – a newer marker, is a metabolite of ethanol formed when an enzyme, phospholipase D binds ethanol to phosphatidylcholine lipids in cell membranes. A positive PEth test result - measuring phosphatidylethanol species 16:0/18:1 – indicates alcohol consumption during the 28 days prior to specimen collection.

The American Heart Association's journal ‘Stroke’ recently published a report of a 22-year study that showed that the likelihood of having an intracerebral haemorrhage was nearly five times higher for those with the highest PEth blood concentrations than those with the lowest concentrations.

At Cansford, we are often asked by medical doctors to explain the difference between CDT and PEth testing – we do so here below:

References

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8. Helander, A., Böttcher, M., Dahmen, N. and Beck, O., 2019. Elimination characteristics of the alcohol biomarker phosphatidylethanol (PEth) in blood during alcohol detoxification. Alcohol and Alcoholism, 54(3), pp.251-257.
9. Helander, A., Hermansson, U. and Beck, O., 2019. Dose–response characteristics of the alcohol biomarker phosphatidylethanol (PEth)—a study of outpatients in treatment for reduced drinking. Alcohol and Alcoholism, 54(6), pp.567-573.
10. Helander, A., Péter, O. and Zheng, Y., 2012. Monitoring of the alcohol biomarkers PEth, CDT and EtG/EtS in an outpatient treatment setting. Alcohol and alcoholism, 47(5), pp.552-557.
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13. Kenan, N., Larsson, A., Axelsson, O. and Helander, A., 2011. Changes in transferrin glycosylation during pregnancy may lead to false-positive carbohydrate-deficient transferrin (CDT) results in testing for riskful alcohol consumption. Clinica Chimica Acta, 412(1-2), pp.129-133.
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16. Schröck, A., Thierauf, A., Wurst, F.M., Thon, N. and Weinmann, W., 2014. Progress in monitoring alcohol consumption and alcohol abuse by phosphatidylethanol. Bioanalysis, 6(17), pp.2285-2294.
17. Schröck, A., Thierauf-Emberger, A., Schürch, S. and Weinmann, W., 2017. Phosphatidylethanol (PEth) detected in blood for 3 to 12 days after single consumption of alcohol—a drinking study with 16 volunteers. International journal of legal medicine, 131(1), pp.153-160.
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20. Ulwelling, W. and Smith, K., 2018. The PEth blood test in the security environment: what it is; why it is important; and interpretative guidelines. Journal of forensic sciences, 63(6), pp.1634-1640.
21. Viel, G., Boscolo-Berto, R., Cecchetto, G., Fais, P., Nalesso, A. and Ferrara, S.D., 2012. Phosphatidylethanol in blood as a marker of chronic alcohol use: a systematic review and meta-analysis. International journal of molecular sciences, 13(11), pp.14788-14812.
22. Walther, L., de Bejczy, A., Löf, E., Hansson, T., Andersson, A., Guterstam, J., Hammarberg, A., Asanovska, G., Franck, J., Söderpalm, B. and Isaksson, A., 2015. Phosphatidylethanol is superior to carbohydrate‐deficient transferrin and γ‐glutamyltransferase as an alcohol marker and is a reliable estimate of alcohol consumption level. Alcoholism: Clinical and Experimental Research, 39(11), pp.2200-2208.
23. Wurst, F.M., Thon, N., Aradottir, S., Hartmann, S., Wiesbeck, G.A., Lesch, O., Skala, K., Wolfersdorf, M., Weinmann, W. and Alling, C., 2010. Phosphatidylethanol: normalization during detoxification, gender aspects and correlation with other biomarkers and self-reports. Addiction biology.
24. Wurst, F.M., Thon, N., Yegles, M., Schrück, A., Preuss, U.W. and Weinmann, W., 2015. Ethanol metabolites: their role in the assessment of alcohol intake. Alcoholism: Clinical and Experimental Research, 39(11), pp.2060-2072.
25. Johansson, K., Johansson, L., Pennlert, J., Söderberg, S., Jansson, J.H. and Lind, M.M., 2020. Phosphatidylethanol levels, as a marker of alcohol consumption, are associated with risk of intracerebral hemorrhage. Stroke51(7), pp.2148-2152.