Accredited legal blood alcohol testing

AlphaBiolabs specialises in legal alcohol testing. We have worked with solicitors and local authorities for over 20 years, and our legal testing is recognised and admissible to UK courts.

We offer four types of blood alcohol test: PEth, the gold standard of blood alcohol tests, CDT, LFT and MCV. Your dedicated Account Manager will be able to advise on which tests are most suitable for your case. Our PEth test is performed using a finger prick device, ideal for Sample Donors who are needle phobic or have poor vein access. PEth is also the only blood alcohol test that can be performed during pregnancy or within two months of birth.

Blood alcohol testing methods

Blood alcohol tests are used to measure the level of alcohol in an individual’s blood. When alcohol is consumed, it is absorbed into the bloodstream and about 90% of it is broken down in the liver. The rest is passed out of the body in urine and exhaled breath. On average it takes the liver about 1 hour to break down 1 unit of alcohol. If a person is drinking excessively, and over an extended period of time, the effects on the liver and other cells in the body can be measured by analysing biomarkers in the blood.

AlphaBiolabs offers the following blood alcohol tests:

  • Finger prick phosphatidylethanol (PEth) test
  • Carbohydrate Deficient Transferrin (CDT) test
  • Liver Function Test (LFT)
  • Mean Corpuscular Volume (MCV) test
  • Comprehensive Alcohol Analysis Package: combines head hair alcohol testing with blood alcohol tests and includes an Expert Report and sample collection.

Blood alcohol testing methods:

Finger prick PEth Alcohol Test

Phosphatidylethanol (PEth) is a direct biomarker of alcohol, meaning that it requires ethanol (the intoxicating agent in alcoholic drinks) for its production, and can only be detected when alcohol has been consumed.

This makes PEth testing the most accurate of the blood alcohol tests.

It can be used to detect chronic and single-drinking episodes, monitor abstinence, drinking behaviour and relapse, and to verify whether an individual has changed their pattern of alcohol consumption.

It is also the only blood alcohol test that can be performed during pregnancy or within two months of birth.

An AlphaBiolabs PEth test simply requires a few drops of blood, collected using a finger prick device. This quick, virtually pain-free method of blood sample collection is ideal for Sample Donors who are needle phobic or have poor vein access.

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Carbohydrate deficient transferrin (CDT)

In cases where a sample donor is excessively using alcohol, an elevated carbohydrate deficient transferrin (CDT) reading is usually seen.

Transferrin is a protein largely made in the liver that regulates an individual’s iron absorption into the blood. It attaches iron molecules and transports them to the bone marrow, spleen and liver. An individual who drinks too much alcohol increases certain types of transferrin that are carbohydrate-deficient. When CDT increases, it can be measured in the bloodstream and is therefore a biomarker of alcohol abuse.

People who do not drink, or drink moderately, will have lower CDT levels in their blood. But people who drink four or more drinks a day, at least five days a week for 2 weeks prior to the test will have CDT at significantly greater levels. The CDT test can thus detect heavy alcohol consumption over a long period of time and is a measure of chronic alcohol consumption. If a person stops drinking, the CDT levels will return to normal levels within 4 weeks. If they start drinking again, the levels will once again rise.

Liver function test (LFT)

Alcohol can be toxic to the liver. A person who consumes excessive amounts of alcohol will damage their liver and may experience decreased liver function. A liver function test (LFT) measures three enzymes in the blood that are produced by the liver. An abnormal result indicates a problem with the liver. For example, an elevated aspartate aminotransferase (AST) value is a biochemical indicator of possible alcohol abuse.

The panel of markers tested include AST, alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) to ensure the result is as accurate as possible.

Mean corpuscular volume (MCV)

Mean corpuscular volume (MCV) refers to the size of red blood cells. Red blood cells carry oxygen in blood to all parts of the body. Heavy drinking over longer periods damages the bone marrow where the red blood cells are produced. The effect is that the red blood cells develop abnormally and become large. As a result, the MCV index becomes higher than normal.

Elevated MCV is common in alcoholics. The changes in red blood cell development persists as long as drinking continues. MCV takes several weeks of heavy drinking to become elevated. However, alcohol-induced bone marrow damage is reversible. Although, it may take several months before MCV returns to a normal level after abstinence.

Some unrelated conditions can result in higher MCV levels. The test is less specific for alcohol abuse in patients with conditions that can influence the size of red blood cells, such as vitamin deficiencies, liver disease, underactive thyroid disease and smoking.

As a stand-alone alcohol abuse indicator MCV has somewhat low sensitivity. However, when combined with the other blood markers it can support a diagnosis of excessive drinking.

Combined blood and hair alcohol testing

We also offer a Comprehensive Alcohol Analysis Package, which combines head hair testing with blood tests and includes a Statement of Witness report and sample collection. This comprehensive package provides the best insight into an individual’s level of alcohol consumption.

This is a popular testing package for family law courts.

Chronic and excessive alcohol consumption can be determined

UK sample collection

AlphaBiolabs has a full UK network of sample collectors who are able to take your client’s legally admissible blood samples at any address of your choice. In addition, any of our 19 UK and Ireland Walk-in Centres offer free sample collection.

View our Walk-in Centres

More alcohol testing services

As well as blood alcohol tests, AlphaBiolabs has other alcohol testing solutions including instant breath tests and 3- or 6-month hair analyses to show alcohol consumption over a period of time. Real-time results are also available with SCRAM Continuous Alcohol Monitoring®.

For expert advice, please call Customer Services on 0333 600 1300 or email us at

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