What is the difference between Phosphatidylethanol and CDT? An explanation for medical practitioners

Lolita Tsanaclis

Lolita Tsanaclis

on 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:

CDT vs PEth - for Drs


1. Aboutara, N., Jungen, H., Szewczyk, A., Sterneck, M., Müller, A. and Iwersen‐Bergmann, S., 2021. Analysis of six different homologues of phosphatidylethanol from dried blood spots using liquid chromatography–tandem mass spectrometry. Drug Testing and Analysis, 13(1), pp.140-147.
2. Anton, R.F. and Moak, D.H., 1994. Carbohydrate‐deficient transferrin and γ‐glutamyltransferase as markers of heavy alcohol consumption: Gender differences. Alcoholism: Clinical and Experimental Research, 18(3), pp.747-754.
3. Arndt, T., 2001. Carbohydrate-deficient transferrin as a marker of chronic alcohol abuse: a critical review of preanalysis, analysis, and interpretation. Clinical chemistry, 47(1), pp.13-27.
4. Bertholet, N., Winter, M.R., Cheng, D.M., Samet, J.H. and Saitz, R., 2014. How accurate are blood (or breath) tests for identifying self-reported heavy drinking among people with alcohol dependence? Alcohol and alcoholism, 49(4), pp.423-429.
5. Bortolotti, F., Raffaelli, R., Di Simone, N., Semprebon, M., Mirandola, M., Simonetto, C., De Marchi, F., Trevisan, M.T., Carli, G., Dorizzi, R.M. and Scambia, G., 2020. CDT reference values for monitoring chronic alcohol abuse in pregnancy. Clinica Chimica Acta, 507, pp.156-160.
6. Fagan, K.J., Irvine, K.M., McWhinney, B.C., Fletcher, L.M., Horsfall, L.U., Johnson, L., O’Rourke, P., Martin, J., Scott, I., Pretorius, C.J. and Ungerer, J.P., 2014. Diagnostic sensitivity of carbohydrate deficient transferrin in heavy drinkers. BMC gastroenterology, 14(1), pp.1-6.
7. Golka, K. and Wiese, A., 2004. Carbohydrate-deficient transferrin (CDT)—a biomarker for long-term alcohol consumption. Journal of Toxicology and Environmental Health, Part B, 7(4), pp.319-337.
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.
11. Isaksson, A., Walther, L., Hansson, T., Andersson, A., Stenton, J. and Blomgren, A., 2018. High-throughput LC-MS/Ms method for determination of the alcohol use biomarker phosphatidylethanol in clinical samples by use of a simple automated extraction procedure—preanalytical and analytical conditions. The Journal of Applied Laboratory Medicine, 2(6), pp.880-892.
12. Jones, J., Jones, M., Plate, C. and Lewis, D., 2011. The detection of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanol in human dried blood spots. Analytical Methods, 3(5), pp.1101-1106.
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.
14. Madhubala, V., Subhashree, A.R. and Shanthi, B., 2013. Serum carbohydrate deficient transferrin as a sensitive marker in diagnosing alcohol abuse: a case–control study. Journal of clinical and diagnostic research: JCDR, 7(2), p.197.
15. Pronicka, E., Adamowicz, M., Kowalik, A., Płoski, R., Radomyska, B., Rogaszewska, M., Rokicki, D. and Sykut-Cegielska, J., 2007. Elevated carbohydrate-deficient transferrin (CDT) and its normalization on dietary treatment as a useful biochemical test for hereditary fructose intolerance and galactosemia. Pediatric research, 62(1), pp.101-105.
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.
18. Stibler, H., 1991. Carbohydrate-deficient transferrin in serum: a new marker of potentially harmful alcohol consumption reviewed. Clin Chem, 37(12), pp.2029-2037.
19. Tsanaclis, L., Davies, M., Bevan, S., Nutt, J., Bagley, K. and Wicks, J., 2021. Testing venous carbohydrate‐deficient transferrin or capillary phosphatidylethanol with concurrent ethyl glucuronide and ethyl palmitate hair tests to assess historical and recent alcohol use. Drug Testing and Analysis, 13(1), pp.203-207.
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.

Hair testing for drug and alcohol guide for Social Workers

Lolita Tsanaclis

Lolita Tsanaclis

Dr. Lolita Tsanaclis, Chief Scientific Officer of Cansford Laboratories Limited, has been developing methods for the analysis of drugs in hair since 1993. She has been involved in drug testing using hair, blood and oral fluid samples for medico-legal and workplace sectors for over three decades. Dr Tsanaclis is published extensively as author and as co-author in highly regarded peer-reviewed publications and scientific presentations.

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