Workplace drug and alcohol testing plays an important role in supporting health, safety and compliance across industries. Most programs rely on urine, oral fluid and breath testing, which are well‑established, standardised methods for detecting recent drug and/ or alcohol use.
In some circumstances, however, employers may need insight beyond short detection windows – particularly when managing safety‑critical risk, rehabilitation programs and/or ongoing compliance requirements. In these cases, hair testing, sweat drug patch testing and PEth testing may be considered as complementary options within a broader testing framework.
This article outlines when and why Australian and New Zealand workplaces may consider these additional testing methods, and how they fit alongside traditional approaches.
Understanding Detection Windows and Test Purpose
No single drug and/or alcohol test can answer every risk question. Each testing method is designed to detect use over a particular timeframe and for a specific purpose.
- Oral fluid testing is commonly used to detect recent drug use. It is governed by AS/NZS4760:2019, with detection typically ranging from minutes to approximately 24 – 48 hours, depending on the substance, donor and pattern of use.¹
- Urine testing, governed by AS/NZS 4308:2023, is widely used for pre‑employment and workplace testing. Detection windows vary by drug class, dose and frequency of use, generally ranging from hours to several days, and longer in cases of repeated or chronic use.¹
- Breath alcohol testing remains essential for immediate safety decisions and is governed by AS 3547.1:2019, regarding breathalyser use.
Hair, Sweat Drug Patch and PEth testing are Not Replacements
For these methods – instead, they are used when organisations need to assess:
- Longer‑term patterns of use,
- Sustained abstinence, or
- Continuous compliance, rather than a single point‑in‑time result
This layered approach aligns with Australian and New Zealand work health and safety expectations that controls be risk‑based, proportionate and defensible.
Hair Testing to Assess Long‑Term Patterns of Use
Hair testing is a useful tool for investigating long‑term use patterns of drugs (and selected alcohol markers) in order to establish a history and/or pattern of use. When substances enter the bloodstream, the drug and/or its metabolites become incorporated into the hair matrix as hair grows.
As head hair grows at approximately 1 cm per month, analysing a defined length of hair allows assessment of exposure over a corresponding time period. Hair testing does not indicate impairment at a specific moment. Instead, it provides insight into historical exposure and patterns of use.
Common Workplace and Professional Use Cases (Hair Testing)
Hair drug testing may be considered where workplaces need to:
- Assess long‑term drug use history rather than recent use
- Support pre‑employment screening for high‑risk and/or safety‑critical/sensitive roles
- Monitor abstinence or reduced use in rehabilitation and/or return‑to‑work programs
- Provide evidence in legal, medico‑legal and/or regulatory contexts
In Australia and New Zealand, while there is no standalone Standard for hair testing, best practice is guided by Society of Hair Testing (SoHT) recommendations on collection, analysis and interpretation.
Sweat Drug Patch Testing (Continuous Monitoring)
Sweat drug patch testing enables continuous drug monitoring over a defined wear period, commonly 10 to 14 days. The patch is worn on the skin and collects drug metabolites excreted through sweat.
When applied and removed under full chain‑of‑custody conditions, sweat patch testing can identify drug exposure that occurs at any time during the monitoring period.
Common Workplace and Compliance Use Cases (Sweat Drug Patch)
Sweat drug patch testing may be considered where:
- Continuous monitoring is required to reduce testing gaps
- Repeated urine and/or oral fluid testing is impractical
- Abstinence must be demonstrated over days or weeks
- Compliance programs require ongoing oversight rather than snapshot testing
The sweat drug patch may also act as a behavioural deterrent in monitored programs. It is typically used alongside, not instead of, traditional testing methods.
PEth Testing (Insight into Alcohol Use Over Recent Weeks)
Phosphatidylethanol (PEth) is a specific, direct biomarker of alcohol consumption that is formed only in the presence of ethanol. PEth testing is more specific than indirect alcohol markers, which may be influenced by medical conditions and/or medications.
PEth reflects alcohol consumption over a consistent detection window of approximately 30 days. This monitoring period does not change based on drinking patterns; however, the level of PEth detected can be influenced by how alcohol is consumed.
For example, consuming a larger amount of alcohol over a short period (such as binge drinking over a weekend) will typically result in higher PEth levels than consuming the same total amount spread evenly over the 30‑day period.
Common Workplace and Professional Use Cases (PEth Testing)
PEth testing may be used to:
- Support return‑to‑work and/or fitness‑for‑duty assessments
- Verify abstinence and/or reduced alcohol use
- Monitor compliance in safety‑critical/sensitive roles
- Assist rehabilitation, clinical and/or medico‑legal programs
Collection involves a simple finger prick to obtain several drops of blood, which are stored for laboratory analysis. This allows for convenient, minimally invasive sampling under full chain‑of‑custody conditions.
Using Advanced Testing Methods in Australian and New Zealand Workplaces
Australian and New Zealand work health and safety legislation requires employers to take reasonable steps to manage risks associated with drugs and alcohol.
Effective drug and alcohol testing programs are supported by:
- A clear, consulted drug and alcohol policy and procedures
- Consideration of the risk profile of the role or environment
- Use of appropriate, defensible drug and alcohol testing methods
- Fair, consistent application supported by training and education
Hair, sweat drug patch and PEth testing can strengthen a drug and alcohol program when used appropriately, with a clear understanding of what each method can – and cannot – provide.
Choosing the Right Test for the Right Purpose
Effective workplace drug and alcohol testing programs recognise that:
- Urine and/or oral fluid testing are essential for detecting recent use and potential impairment
- Hair testing provides insight into longer‑term patterns
- Sweat drug patch testing allows continuous monitoring
- PEth testing supports assessment of alcohol use over weeks, not hours
Please note that your Drug and Alcohol Policy and Procedure must including guidelines for using additional specialist testing services including Hair, Sweat Drug Patch and PEth Testing. Understanding detection windows, cut‑off thresholds and limitations is critical to ensuring drug and alcohol test results are interpreted correctly and applied fairly.
Contact our team to explore how these methods can support your workplace risk and compliance requirements.