It is therefore essential that family lawyers know what they are talking about when it comes to a blood alcohol test.
According to Harriet Challenger, laboratory manager (toxicology) at AlphaBiolabs, courts use four main types of blood tests to provide a four-week alcohol history, of which the phosphatidylethanol (PEth) test is the most conclusive.
While PEth provides a direct biomarker of alcohol, the other three ―Carbohydrate Deficient Transferrin (CDT), Liver Function Test (LFT), and Mean Corpuscular Volume (MCV) ―provide indirect biomarkers of alcohol, and their results can be affected by medical conditions and medications.
PEth production begins as soon as ethanol is consumed and accumulates in the blood with frequent alcohol consumption, giving it high specificity (48%-89%) and sensitivity (88%-100%).
Consumption experiments show that PEth can be detected in the blood after one to two hours, and up to 12 days after a single consumption episode. In addition, a daily alcohol consumption of more than 60 g of ethanol (7.5 units) can be clearly distinguished from a lower alcohol consumption. This means that PEth tests can detect chronic and single-use episodes.
Challenger asserts that the wealth of information provided by a PEth test, as well as its conclusive nature, make it the most essential of all alcohol tests, enabling courts to monitor abstinence, drinking behavior or identify relapses, a particularly important factor when working with families and children affected by alcohol abuse.
The PEth test is also the only blood alcohol test that can be done during pregnancy or within two months of giving birth.
Hair tests are another way to measure alcohol consumption. Challenger claims that PEth is second only to the detection of ethyl glucuronide (EtG) and ethyl palmitate (EtPa): a fatty acid ethyl ester (FAEE) in hair.
EtG and EtPa are direct biomarkers of alcohol and provide very accurate insight into drinking patterns, with a three- or six-month view of usage. Each is absorbed into the hair through different routes, and their levels can help gauge excessive alcohol consumption.
EtG can be affected by various hair treatments, including excessive washing, as it is water soluble and produced in the liver.
EtPa can be affected by the use of alcohol-containing hair products such as sprays, gels, and wax because it is lipophilic (not soluble in water) and formed in the sebaceous glands from ethanol diffusing from the bloodstream, then deposited in the hair mainly from sebum (from the sebaceous glands of the scalp).
In LB Richmond vs. B&W&B&CB  EWHC (2903) Fam, Justice Moylan gave guidance on the probative value of hair strand testing. He stressed that hair strand testing should not be used in isolation to draw conclusive conclusions.
Challenger says: “There is no denying that alcohol testing combined with hair testing provides us with the most complete picture from which to draw conclusions.
“This is particularly important in family matters, where the protection of children and vulnerable people is the highest priority. By using highly accurate scientific analysis and examining how the body absorbs alcohol, it is possible to advocate for those in need and reunite families where abstinence has been achieved.
AlphaBiolabs is offering a special 20% offer on all AlphaBiolabs alcohol tests until February 28, 2022 by quoting ALC20 when ordering. E-mail [email protected], call 0330 600 1300 or visit www.alphabiolabs.com for more information.