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Deep dive into Alcohol Testing

By Emily Harris, Reporting Scientist

At Lextox we offer hair alcohol testing for two types of alcohol markers, the fatty acid ethyl ester; Ethyl Palmitate (EtPa) and Ethyl Glucuronide (EtG), to help in the assessment of chronic excessive alcohol consumption. The results obtained from hair testing are accurate; however, we recommend the hair alcohol testing is used in conjunction with blood alcohol testing to provide a clearer picture of a donor’s alcohol consumption.

Lextox offer three main blood tests, phosphatidylethanol (PEth), carbohydrate deficient transferrin (CDT) and liver function. As with all tests there are some considerations; therefore, this blog aims to provide information to understand more about each blood test and how it can be used in conjunction with the hair alcohol marker testing here at Lextox.

Blood tests

Phosphatidylethanol (PEth)

Phosphatidylethanol is an abnormal phospholipid formed in the presence of direct alcohol consumption. PEth is formed in the presence of ethanol and bonds to the membrane of red blood cells. Because PEth is only formed in the presence of alcohol, this makes it a reliable test method for determining alcohol use.

The PEth test covers approximately one month prior to sample collection. Therefore, as the PEth test covers a shorter time period than the hair test it is advantageous to use the PEth test together with hair testing to provide a picture of a donor’s more recent alcohol consumption.

However, PEth has a high diagnostic sensitivity and concentrations of PEth are highly correlated to alcohol intake. As such, the PEth test is extremely helpful in providing information in respect of a donor’s more recent alcohol consumption within the month prior to sample collection, and is not affected by other medical factors, like the other two blood tests

Carbohydrate Deficient Transferrin (CDT)

The CDT test measures the level of carbohydrate deficient transferrin present within the body. Individuals who consume little or no alcohol have a low level of transferrin in the carbohydrate deficient form, whilst individuals who misuse alcohol may have a higher proportion of carbohydrate deficient transferrin within the body.

The exact period of time of alcohol consumption covered by the CDT test cannot be determined however to obtain a positive CDT result an increase in alcohol intake for longer than 2-4 weeks prior to the test is required. It is detailed that a consumption of 50–80 grams of alcohol per day over one week can induce a rise in CDT level.

Therefore, as the CDT test covers a shorter time period than the hair test it is advantageous to use the CDT testing together with hair testing to provide a picture of a donor’s more recent alcohol consumption.

A consideration with CDT is that pregnancy can cause an elevation in the CDT level; therefore, it is preferable that if the gestational period is known to be in the second or third trimester in the first instance, to avoid CDT testing and to refer to other markers of excessive alcohol consumption. Furthermore, it is possible for an individual to be drinking excessive levels of alcohol and not have an elevated CDT level. As such, a negative CDT result, cannot be used to definitively show an individual has not consumed excessive levels of alcohol.

Liver Function (LF) Test

The LF test measures the levels of enzymes and proteins that are produced by or are involved in liver function and provides an assessment of the health of the liver at the time of the sample collection. One of the functions of the liver is to break down alcohol within the body; therefore, regular heavy drinking can affect a number of the enzymes and proteins within the liver. This can result in some of the enzymes and proteins being raised to above the normal ranges.

A consideration with LF is that the liver is an organ which can constantly repair itself, as such once an individual stops consuming alcohol, even for a short period of time, the liver can, in some cases, begin to repair itself and the markers can return to within the normal levels. In some cases this can take some time; therefore, a liver function test is unable to determine when alcohol has been consumed. In addition, some individuals do not show any abnormal liver function despite excessive alcohol consumption over an extended period of time. Furthermore, an LF test is not just specific to alcohol, so can show other abnormalities that may not be required or pertinent to a case; whereas PEth, for example is very specific.

However, certain markers, if raised, can be used to indicate the possibility of excessive alcohol consumption. The most widely used tests for heavy alcohol consumption are for gamma GT (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT).

In summary, it is advantageous to use blood testing together with hair testing in order to provide a more detailed overall picture of a donor’s alcohol consumption.

At Lextox, we help detect alcohol substance, helping establish the presence or absence of alcohol in a person’s system. This information is vital and can determine child custody or visitation rights. To find out more about drug and alcohol testing please call us on 029 2048 4141 or email [email protected]

Published 29/06/23 – All information correct at time of publication