Blood Alcohol Testing

Accredited legal blood alcohol testing

AlphaBiolabs specialises in legal alcohol testing. We have worked with solicitors and local authorities for over 15 years, and our legal testing is recognised and admissible to UK courts.

We offer four types of blood alcohol test. Your account manager will be able to advise you on which test is right for your case, saving you time and money, and importantly providing the answers you need to stand up in court. Please note that blood can’t be collected during pregnancy or up to 2 months after the birth of a baby. However, phosphatidylethanol (PEth) testing can be undertaken during pregnancy.

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:

• Phosphatidylethanol (PEth)
• Carbohydrate deficient transferrin (CDT)
• Liver function test (LFT)
• Mean corpuscular volume (MCV)
• Comprehensive Alcohol Analysis Package, which combines head hair testing with blood tests and includes a Statement of Witness report and sample collection.

Phosphatidylethanol (PEth)

Phosphatidylethanol (PEth) is the most accurate of the blood alcohol tests. This is because PEth is a direct marker of alcohol, which means that it can only be detected when alcohol has been consumed. It requires ethanol for its production and is formed on the surface of a red blood cell when the alcohol reacts with phosphatidylcholine. Its high specificity (48–89%) and sensitivity of 88–100% is because it is directly related to alcohol consumption.

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

Another advantage of PEth is that blood can be tested with caution during pregnancy and immediately after the birth of a baby.

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.