Top 10 Drug & Alcohol Testing Myths – Busted!
Myth #1: Hair strand testing works the same for drugs and alcohol

Drug and alcohol testing carries real weight in family law, informing decisions on contact, custody and safeguarding.

But misconceptions about how laboratory testing works are common, even among the most experienced social workers and family law professionals.

In this series, we’re setting the record straight on the top 10 drug & alcohol testing myths that are most persistent, so you’re fully equipped to instruct the right tests for your case and interpret the results with confidence.

MYTH #1: Hair strand testing works the same for drugs and alcohol

Hair drug testing and hair alcohol testing both use a cut hair sample, both offer a detection window of up to 12 months, and samples for both tests are collected in the same way – by a professional sample collector under chain of custody conditions.

But how each test works and what the result tells you is completely different, due to how drugs and alcohol find their way into the hair.

Why people believe this myth

For hair drug and alcohol testing, the sample types and collection process are identical, and both tests offer the same headline detection window.

For a family law professional or social worker instructing a test, there’s therefore little reason to expect the laboratory analysis to differ, or the Expert Report to be presented differently once the results come back.

The facts

The key difference comes down to how each substance gets into the hair.

Drugs and drug metabolites travel into the bloodstream and become trapped inside the medulla, the innermost layer of the hair shaft, as it grows.

Alcohol biomarkers, by contrast, are deposited onto the hair rather than being trapped inside it: Ethyl Glucuronide (EtG) via sweat, and Ethyl Palmitate (EtPa/FAEE) via sebum, the oily substance secreted by glands in the scalp.

That single distinction is what drives every difference shown in the table below.

	Hair Drug Testing	Hair Alcohol Testing
What it looks for	Drugs and their metabolites	Two direct alcohol biomarkers: EtG and EtPa (FAEE)
How it gets into the hair	Trapped inside the medulla as hair grows	Deposited onto the hair via sweat (EtG) and sebum (EtPa)
Head hair analysis	Segmented (month-by-month) or overview, up to 12 months	Segmented or overview, up to 12 months
Body hair analysis	Overview only (growth rate too inconsistent to segment), up to 12 months	Overview only, and EtG only, as the body lacks the scalp’s oil glands needed to deposit EtPa
What the Expert Report shows	Specific substances detected, and at what concentration, against cut-off levels	Whether EtG and EtPa levels indicate chronic and excessive consumption, or support abstinence, against cut-off levels
What can affect the results	Hair treatments (excessive bleaching, dyeing, perming, straightening)	EtG: hair treatments and excessive washing. EtPa: largely unaffected by treatments, but levels can be raised by alcohol-based styling products (hairspray, gel, wax)

Both test types are assessed against cut-off levels, which are international and scientifically established thresholds set by the Society of Hair Testing.

Because hair treatments and products have the potential to impact the results of hair drug and alcohol tests in different ways, our professional sample collectors always ask sample donors about hair treatments and recent product use at the point of collection.

Medications add another layer of complexity that our scientists need to account for when testing hair for drugs.

Codeine, for example, is metabolised by the body into morphine, so a positive morphine result does not automatically point to heroin use. Some ADHD medications can also produce findings that overlap with those associated with illicit amphetamine use.

This is why full disclosure of medications, doses and prescription history at collection matters just as much as disclosing hair treatments, and why every result is interpreted carefully, considering the wider context of the case.

Learn more: Hair drug testing for court
Learn more: Hair alcohol testing for court

What this means in practice

For family law professionals, social workers, and local authority caseworkers, this means the results of hair drug tests and hair alcohol tests should not be relied upon to tell the whole story on their own.

It’s a useful reminder that hair testing, whether for drugs or alcohol, works best as part of a wider evidential picture rather than in isolation. 

If you’re instructing drug testing or alcohol testing for a family court matter and want advice on the right combination of tests for your case, our expert team can help.

Contact our New Enquiry team on 0333 600 1300, email testing@alphabiolabs.com, or complete our online quote form

For Myth #2, we’re looking at whether it’s difficult to conduct drug or alcohol testing on someone with little or no hair.