Blood Testing

Blood testing for alcohol markers can be a useful adjunct to hair and urine testing or as part of an ongoing monitoring regime. The results should not be used in isolation of other evidence.

The assessment of alcohol consumption is best carried out using several analytical tests and other factors.


Indirect alcohol markers include liver function tests, in particular gamma glutamyl Transferase (GGT), mean corpuscular volume (MCV) and Carbohydrate-deficient Transferrin (CDT).  In general, these markers are enzymes or cell changes occurring in response to acute or chronic alcohol consumption.


Direct alcohol markers are created when alcohol is metabolized or reacts with substances in the body. Phosphatidylethanol (PEth) is a direct alcohol marker produced after alcohol exposure in cell membranes. It is reported to be independent of gender, age and liver disease, is highly specific and has a detection window of up to several weeks after alcohol intake.

Although no international consensus exists at present for the interpretation of PEth concentrations in blood, its application potential is broader than for many other alcohol markers and can be useful in the overall assessment of alcohol use.

Blood Collection

Blood collections are carried out using a standardised evacuated blood collection system, supplied by the laboratory. The collected sample is dispatched to the laboratory for analysis. There is no provision for the collection of a ‘B’ sample for this type of testing. Sample integrity systems are typical of those used in clinical laboratories.



Blood Analysis

Blood samples are analysed by CPA/ISO accredited laboratories. Results are accompanied with general interpretative information such as reference ranges and may or may not include interpretive comments specific for a particular case.


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