17/12/2025Which Method of Alcohol Testing Is Right for Your Case?
According to August 2025 data from Alcohol Change UK, 32% of men and 15% of women regularly consume more alcohol than the Chief Medical Officers' low-risk drinking guidelines recommend. Those guidelines state adults shouldn't drink more than 14 units a week, spread evenly over three or more days. This equates to 7 medium glasses of wine or 7 pints of average strength beer per week. One of the major risks is the associated health issues. Those include:
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Increased risk of multiple forms of cancer
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Heart disease
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Liver disease
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Strokes
Excessive alcohol consumption is also frequently stated as a risk factor for increasing the likelihood of some common legal cases, such as:
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Domestic abuse
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Child protection cases
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Road traffic accidents
Below, we've created a comprehensive guide that explains the different methods used in UK legal cases that can accurately confirm alcohol consumption.
Hair Alcohol Testing
For ongoing legal proceedings where excessive alcohol consumption is suspected, hair alcohol testing can tell the court whether there has been a consumption of alcohol of more than 60 grams per day over a prolonged period. In units, 60 grams per day translates to approximately 7-8 units per day, which is just under a bottle of wine or 2-3 pints of lager.
Due to its volatile nature, it is not possible to measure ethanol itself in hair samples. Therefore, at AttoLife, we analyse two direct alcohol biomarkers produced by the liver after ethanol is ingested: ethyl glucuronide (EtG) and ethyl palmitate (EtPa), which is a subset of fatty acid ethyl ester (FAEE) testing.
EtPa & EtG are more stable than ethanol and, as such, can both be found in the hair strand, with EtPa absorbed through the secretion of the sebaceous glands and EtG absorbed through the blood.
When assessing chronic excessive alcohol consumption, it is not recommended to segment the hair into monthly sections. Following the Society of Hair Testing (SoHT) guidelines, hair segments should be between 3 and 6cm in length in order to give the most reliable results. However, when assessing for abstinence from alcohol consumption, segmentation into 1cm segments can prove useful to allow greater sensitivity for detecting low and infrequent drinking events.
While hair analysis is good for assessing an individual’s average alcohol consumption over a specified time, it is not possible to identify the exact amounts used or how frequently alcohol was consumed, nor to specify when drinking events occurred. That said, there's extensive scientific literature that proves the validity of this testing method. It's also court-approved since the landmark UK family law case LB Richmond v B & W [2010] EWCA 2903.
AttoLife professionally trained samplers will aim to take, if possible, samples of hair from the 'posterior vertex region' (back of the crown) because hair growth here is typically thickest, has the most consistent growth rate, and is usually more discreet for cosmetic reasons.
The main limitations of the test are that results can be inaccurate when cosmetic treatments are used. Hair becomes damaged by the use of bleaching, dyeing, and heat treatments and can potentially cause a reduction in concentration for both biomarkers. EtPa can also potentially increase in concentration when alcohol-containing products are used on the hair.
Fingernail Alcohol Testing
Fingernail alcohol testing is another excellent method offered by AttoLife for detecting ongoing, excessive alcohol consumption. Although the sample collection method and laboratory analysis processes are slightly different, fingernail alcohol testing still relies on EtG biomarkers to identify alcohol consumption, but not EtPa. As ethanol converts to EtG in the liver, it travels through the bloodstream and becomes embedded in the fingernails through the nail bed capillaries.
It's worth noting that whilst hair alcohol testing is one of the most excellent types of alcohol tests, EtG levels are found in higher concentrations in fingernail samples. In 2012, a study analysing the levels in fingernail and hair samples taken from 606 college students showed that fingernail-positive samples were 2.5 times higher than in hair samples.
What's interesting about fingernail alcohol testing is that fingernail keratin is 4x thicker than hair keratin fibres. It was previously assumed that substances could only be found in the germinal matrix that emerges from the nail root, with new keratin added to the underside of the nail bed as it grows. Science, however, has proven that the blood vessel continuously feeds the growing nail, so alcohol biomarkers are embedded in the keratin fibres over the entire fingernail growth timeline.
For alcohol misuse testing, a sample of the fingernail is clipped from the leading edge of the nail growth, with the ideal sample size for a positive result being around 100 mg of fingernail, or a 2-3 mm clipping.
The limitation is that alcohol can’t be detected until 1-2 weeks after consumption, so there's a period of delay after initial alcohol misuse. Nails are also much slower growing, and, like alcohol hair testing, it's impossible to pinpoint the exact date of misuse.
Blood Alcohol Testing
Alcohol blood testing is one of the most commonly requested tests in legal proceedings, especially immediately after incidents such as road traffic accidents. The old testing methods were CDT, LFT and MCV. A venepuncture blood analysis sample would look for indirect alcohol markers with a detection window of 2-4 weeks. The detection potential depended on factors such as:
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Amount of alcohol consumed
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Individual metabolism
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Liver health
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Overall health
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Smoking
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Liver diseases
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Genetics
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Certain medications (antibiotics, antidepressants, antihistamines)
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Hydration levels
At AttoLife, we use the gold standard of testing for the phosphatidylethanol (PEth) biomarker using a finger prick to form a droplet of blood, which is then spotted onto a collection device. This is much less invasive than other forms of blood testing that require liquid blood to be collected using a needle.. Detection of PEth is far more accurate, with minimal factors affecting the results, unlike the old CDT, LFT and MCV indirect marker analysis methods. It's a more specific test with low false positive rates and a detection window of one month.
PEth testing is widely recognised and legally accepted as a definitive method for determining previous alcohol consumption behaviours. Another advantage of PEth testing is that it can be used in conjunction with hair testing to investigate the most recent 1-2 weeks of drinking, which, in the case of hair, is trapped under the scalp.
SCRAM Testing (Continuous Alcohol Monitoring)
The SCRAM CAM Continuous Alcohol Monitoring® device is one of the most innovative types of alcohol tests on the market. Unlike any of the testing methods we've mentioned so far, this testing method provides 24/7 alcohol monitoring through an ankle bracelet. Essentially, the SCRAM CAM uses transdermal detection of ethanol excreted through the pores during perspiration. Interestingly, 95% of alcohol is metabolised by the liver, with 4% excreted through the kidneys and lungs and 1% through the skin during perspiration.
That's why, sometimes when an individual has consumed excessive amounts of alcohol, you can still smell it on them the next day.
When someone wears the SCRAM CAM®, the bracelet performs a detection "sniff" every 30 minutes. There's a pump inside the SCRAM CAM® that takes the sample, and a fuel cell reacts with any ethanol to determine the presence of alcohol.
Unlike the alcohol testing methods we've mentioned so far, the bracelet can't detect historic alcohol misuse. It is, however, excellent for providing real-time data and analysis. And as the measurement focuses on transdermal alcohol concentration, the device can accurately determine a positive alcohol consumption result at a minimum TAC of 0.020. That translates to a Blood Alcohol Content (BAC) of around 0.02%, or one to three drinks, depending on a person's weight and body composition.
SCRAM testing is ideal for alcohol monitoring when an individual needs to prove that they have not been drinking (abstinence) or are sober on certain days of the week.
Urine Alcohol Testing
In legal circles, urine alcohol testing is one of the lesser-used testing methods now, but it's not uncommon for it to be used alongside other alcohol testing methods in court cases to improve the validity of a positive result.
Similar to the other testing methods we've discussed, urine alcohol tests aim to detect metabolites, with the primary biomarkers being ethyl glucuronide (EtG) and ethyl sulphate (EtS).
Urine alcohol tests won't typically look for the presence of ethanol alcohol directly because the body typically eliminates it within 12 hours. EtG and EtS metabolites are detectable for between three and five days, depending on a person's metabolism and other factors such as liver health, genetics, and overall health.
If a urine screening alcohol test is positive, it's often followed up with a confirmatory test such as Gas Chromatography-Mass Spectrometry to improve the accuracy of the result.
Get in Touch
If you need any help or advice to understand the most suitable alcohol testing method for your situation, call one of our friendly team members today on +44 020 3551 1493. You can also send us an email at [email protected].