As a manager in a manufacturing plant, you’ve seen and heard it all. Until this morning. One of your employees has returned a non-negative result for opiates. When questioned, he strongly denies using heroin or any medication. Instead, he points to his breakfast — two poppy seed bagels before work.
It might sound like a tall story. But is it possible? And what’s this got to do with drug testing cut-off levels?
Before we look at whether it’s possible to have a non-negative result from eating bagels, let’s look at one of the most misunderstood aspects of workplace drug testing: cut-off levels. What are they, and why are they something that employers should know about?
What are drug testing cut-off levels?
A cut-off level is the minimum concentration of a drug or its metabolites that must be present in a sample for the result to be reported as non-negative.
If the concentration is below this level, the result is reported as negative, even if trace amounts of the substance are still present.
Cut-off levels are typically measured in:
- Urine testing: micrograms per litre (µg/L)
- Oral fluid (saliva) testing: nanograms per millilitre (ng/mL)
These thresholds are not random. They are carefully defined to balance detection with fairness.
Why cut-off levels exist
Cut-off levels are designed to achieve three key outcomes:
- Reduce false non-negative results. Trace exposure to certain substances can occur through environmental contact or legal medication. Cut-offs help ensure non-negative results from trace exposures don’t occur regularly.
- Focus on recent or relevant use. Workplace drug testing in Australia is concerned with safety and fitness for work. Cut-off levels are set to detect levels more consistent with recent drug use rather than historical traces.
- Ensure consistency. By applying standardised thresholds, results and the way results are interpreted remain more consistent across workplace, industries and providers.
Screening vs confirmatory cut-off levels
Now that you have a better understanding of what cut-off levels are and why we have them, it’s also important to understand the difference between screening and confirmatory testing.
Screening or initial tests provide rapid results to identify people who may be under the influence of drugs. This testing is accurate, but it is not perfect. On rare occasions, false non-negatives can occur.
Confirmatory tests, held in an independent laboratory are conducted using advanced methods, and provide legally defensible results. This analysis is done using liquid chromatography–mass spectrometry (LC-MS). This method is considered the gold standard in drug testing. It not only identifies the class of drug present, such as opiates, but can also determine the specific substance, such as heroin. It also identifies whether the drug was detected above the specific cut-off level.
Australian Standards and why they matter
In Australia, drug testing cut-off levels are defined by national standards:
These standards outline:
- Cut-off levels
- Testing procedures
- Chain of custody requirements
- Reporting protocols
Recent updates to standards have improved accuracy and, in some cases, lowered detection thresholds to better reflect modern drug use patterns.
For employers – and the providers and/or testing kits they use – aligning with these standards is critical. It ensures legal defensibility, consistency, and best-practice workplace safety
What cut-off levels mean for your workplace
Understanding cut-off levels can improve how you design and manage your drug and alcohol policy:
- Clearer decision-making. Knowing how results are determined helps you respond appropriately to non-negative and confirmed results.
- Better communication with employees. Explaining cut-off levels can reduce confusion and build trust in your testing program.
- Stronger compliance and defensibility. Aligning with Australian Standards protects your organisation if results are challenged.
- More effective risk management. Cut-off levels help ensure your testing program focuses on meaningful safety risks, not irrelevant trace detections.
Common myths about cut-off levels
“Any amount of drugs will result in a non-negative screening test”
Not true. Results must exceed defined cut-off levels.
“A non-negative screening result means the employee is guilty”
Incorrect. Confirmation testing is required before a positive result is finalised.
“Lower cut-offs are always better”
Not necessarily. Extremely low cut-offs can increase false non-negatives and reduce fairness.
Contact Integrity Sampling for help
Drug testing cut-off levels are not just technical numbers. They are a critical part of creating a fair, accurate, and effective workplace drug testing program. For employers, the key is not just knowing the numbers but understanding what they mean in practice.
If you’re still unsure about cut-off levels and what it means for your testing, contact Integrity Sampling and we’ll be glad to explain further.
Note: Getting back to one of our original questions, can eating a poppy seed bagel (or two) cause a non-negative drug screen? In rare cases, yes. Poppy seeds naturally contain small amounts of opiates. Consuming a large quantity shortly before a urine test could result in a non-negative result. However, saliva testing is less likely to be affected, and modern cut-off levels are carefully set to minimise these false non-negatives.
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