SCRAM Testing vs. Hair Testing

Up till now, hair strand testing has been considered the gold standard in toxicological analyses. This long-established method can provide a history of drug and alcohol abuse and is routinely used in the forensic and family law fields. However, a novel detection technique that provides a means of continuous alcohol monitoring is gaining popularity and is increasingly being selected by the legal profession. Both detection methods assess alcohol consumption but work in very different ways.

Hair testing works by looking at two markers of alcohol: ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). The level of alcohol consumed will determine the level of these markers in the hair. Both types of markers are absorbed via different routes and their levels can assist in assessing excessive alcohol use by an individual.

The reasons that both EtG and FAEE markers are analysed is because they are affected by external factors in different ways. EtG is produced by the liver and incorporated into the hair, mainly through sweat, and is measured in pg/mg (trillionth of a gram per mg of hair). It is hydrophilic, meaning that it is water soluble. As such, some EtG may be lost through the use of hair dye and excessive hair washing. FAEEs are produced in the blood and incorporated into hair via sebum (an oily substance secreted by glands in the skin). Their levels are measured in ng/mg (billionth of a gram per mg of hair). FAEEs are lipophilic and therefore not water soluble, so although not affected by hair washing, the amount detected could be affected by use of hairsprays, gels and wax.

Head hair is preferred over body hair for alcohol testing. It is possible to perform both EtG and FAEE analyses on hair samples collected from locations other than the scalp, such as pubic, underarm, chest, arm, leg, abdomen and beard. However, these tests have limitations. Pubic hair can be contaminated with EtG from urine. Underarm and chest hair samples can give false positive FAEE findings following the use of alcohol-containing products such as deodorant and perfume or aftershave.

Court ruling

Because of these respective strengths and weaknesses of EtG and FAEE tests, both tests should be performed and their findings should support each other in order to determine chronic consumption of alcohol. Indeed, as per the London Borough of Richmond vs. B & W & B & CB (2010) EWHC 2903 (Fam) case, the Court ruled that EtG and FAEE tests should always be used together. It went further saying that hair analysis findings should not be used in isolation but in conjunction with all evidence for the case including witness reports, other tests performed and any clinical assessments carried out.

Ideally, the minimum length of hair for EtG and FAEE tests is a 3 cm section taken from nearest the scalp, around 200 individual strands (about the width of a pencil). This is consistent with the consensus on hair alcohol testing for chronic excessive alcohol consumption published by the Society of Hair Testing (SoHT) in June 2009. The result will be considered either above or below the recommended SoHT cut-off levels. The level of biomarker found in the hair can help determine if a person has been drinking chronically and excessively, and will show an overview of 3 or 6 months. Unfortunately, the results will not pinpoint exactly when the drinking occurred.

When analysing hair for drugs, the drug metabolites are absorbed through the root of the hair. This makes it possible to segment the hair and thereby provide a month-by-month historic profile. This isn’t possible with hair alcohol testing as the markers are distributed along the hair, not within it. The result provided will therefore give an average over the length of time tested, which is determined by the length of the sample. When a client consumes alcohol the entire length of the hair is contaminated with alcohol. For example, if your client has not drunk alcohol for 5 months but then drinks an excessive amount in 1 month, the alcohol markers will be found along the entire length of the hair.

Real-time results

An accurate way of pinpointing exactly how much alcohol has been ingested and when is now possible with SCRAM Continuous Alcohol Monitoring® (SCRAM CAM®). This device is a bracelet that is worn on the ankle and tests for the presence of alcohol in perspiration. It is the first device of its kind to detect the drinking of alcohol in real-time and the results are automatically gathered and uploaded to a base station. The base station could be located in the individual’s home, a solicitor’s office or anywhere convenient. A telephone line or internet connection is not essential but would be required for regular analysis and reporting. Incidents of drinking and tampering are recorded and made known weekly, monthly or at the end of the testing programme.

The principle behind this transdermal form of testing is based on how the human body metabolises alcohol. Once alcohol is absorbed and distributed through the bloodstream, it is eliminated in various forms. About 1–2% of the alcohol that is consumed is eliminated through the skin in the form of perspiration. These transdermal emissions are sampled every 30 minutes. As such, the frequency and pattern of alcohol consumption can be easily shown.

The SCRAM CAM® bracelet needs to be fitted to the ankle by a trained person to ensure that it is fitted correctly. The bracelet is water resistant, but shouldn’t be submerged so showers are preferred to baths or swimming. Ideally the bracelet should be worn for 30 days or more as that gives a good overview of the wearer’s drinking behaviour.

This method of testing for alcohol makes it easier to adhere to low or no-alcohol schemes as samples are taken on a continuous basis, every half-an-hour, 24 hours a day, 7 days a week. The technology is so advanced it can even differentiate between very low alcohol consumption (such as 1–2 units) and environmental alcohol sources. This helps enforce participant sobriety, compliance and accountability. This form of continuous monitoring (also called sobriety tagging) can provide local authorities, courts and child-protection agencies with the tools to change behaviours in vulnerable and higher-risk alcohol-dependent clients.

Abstinence cannot be established by means of hair alcohol tests. Research has shown that even individuals who have not consumed alcohol can test positive for both EtG and FAEEs. This can be explained because everyday foods can contain alcohol and endogenous alcohol can be produced via normal human metabolism.

Which to choose?

In terms of pricing, hair strand testing and SCRAM CAM® are comparable. Legal Aid Agency funding is also available for both. So which method of alcohol detection is superior? Both have their pros and cons. To determine the best method for you, the main question to ask is what period of detection do you wish to cover?

Hair strand testing is valuable to form part of an evidential picture when the aim of the testing is to determine whether a person has been overconsuming alcohol, on average, over the testing period. However, the results should ideally be used in conjunction with other forms of testing and other forensic evidence. Transdermal testing is not suitable to gain evidence of past misuse of alcohol; for example, to check if an individual has been truthful about their alcohol intake. So, hair strand testing is the most appropriate method as it can go back for up to 6 months with 6 cm of hair. However, if the court wishes to monitor current and future alcohol intake, SCRAM CAM® is the best option as it tests for alcohol every 30 minutes over specified time periods and provides information on precise drinking events. As such, both testing methods have their uses and both will continue to be heavily relied upon when a definitive decision is needed in cases involving alcohol abuse.

Hair testing vs. SCRAM CAM®

 Hair alcohol testingSCRAM CAM®
What does the test measure?Fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG) alcohol markersEthanol in perspiration
Period of detection3 or 6-month overview1 day up to 4 months
Method of detectionUltra-performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS)Fuel cell technology
Can the test measure the amount of alcohol consumed?No, it is not possible to determine alcohol dose. The result provided will give an average over the length of time tested – which is determined by the length of the sample (3 or 6 months)Yes, the device can measure mg alcohol per 100 ml blood. The report also describes these values as equivalent units of alcohol
Can the test identify the frequency that alcohol is/was consumed?No, it is not possible to determine frequency of alcohol use. Only an average can be measured over a 3 or 6-month time periodYes, the device can pinpoint alcohol use at the exact time of day, which day and which day of the week


Can environmental exposure cause any problems?Yes, excessive use of cosmetic treatments on hair could affect results. Based on guidance from the SoHT it is advised that both EtG and FAEE are analysed together to provide mutual confirmation of the resultAlthough the ankle bracelet is waterproof and tamper-resistant, it can pick up readings from hygiene products containing alcohol. Such products should not be applied to the ankle
Sample collection requirementsAt least 3 cm length of hair and around 200 individual strands are needed (about the width of a pencil), cut as close to the scalp as possibleThe bracelet needs to be fitted to the ankle by a trained person
Is the Chain of Custody procedure legally defensible in court?Yes. Proof of ID, donor’s and collector’s signature, and a photograph of sample donor is collected by the sample collectorYes. ID can be checked and a photograph taken at the time the SCRAM CAM® device is fitted