Should you terminate an employee after a non-negative?
Legal, safety and ethical considerations of results from Australian workplace drug testing services
When a workplace drug test returns a non-negative result, emotions can escalate quickly. Managers may feel pressure to act decisively. However, termination at the non-negative stage is rarely appropriate and may expose your business to significant legal risk.
Understanding how Australian workplace drug testing services operate and what the standards require are critical before making any employment decisions.
First: a non-negative is not a positive
Onsite screening devices used in Australian workplace drug testing services rely on immunoassay technology. These devices are designed to detect drug classes at defined cut-off concentrations under Australian standards (AS/NZS 4308 for urine and AS/NZS 4760 for oral fluid).
A non-negative result simply means:
- the screening device detected a substance at or above the screening threshold
- the specimen must be sent for laboratory confirmation
- no final conclusion has been reached.
Under the standards, interpretation of results must be undertaken by appropriately qualified professionals such as a medical review officer or toxicologist.
Termination at the screening stage would mean acting on a preliminary result that is not yet confirmed.
Why confirmation matters
Laboratory confirmation uses highly specific techniques such as LC-MS to identify:
- the exact substance present
- its concentration
- whether the finding is consistent with medication, illicit use, or another explanation.
For alcohol testing, a non-negative screening breath result must also be followed by a confirmation test after a waiting period to ensure accuracy.
The difference between screening and confirmation is not technical semantics. It is the difference between a preliminary indicator and a defensible result.
Many screening non-negatives confirm as:
- legitimate prescribed medication use
- negative upon confirmation
- positive but with mitigating factors requiring professional interpretation.
Termination before confirmation may be considered procedurally unfair.
Legal considerations
Under Australian workplace health and safety laws, employers must manage risks, including impairment. However, employment decisions must also comply with:
- Fair Work Act obligations
- procedural fairness requirements
- anti-discrimination laws
- contractual and policy commitments.
If a workplace policy states that disciplinary action follows a confirmed positive result, terminating after a non-negative screening may breach your own policy. Just like in this expensive case.
Courts and tribunals consistently examine whether:
- the policy was clear and consistently applied
- the result was confirmed according to Australian standards
- the employee was given an opportunity to respond
- expert interpretation was obtained.
Failure in any of these areas increases exposure to unfair dismissal claims.
Safety considerations
In safety-sensitive roles such as jobs in transport, healthcare, mining and more, standing a worker down pending confirmation is common practice. This is a risk-control measure, not a disciplinary action.
Standing down protects:
- the individual
- coworkers
- the public
- the employer from foreseeable risk.
Immediate termination, however, is rarely necessary to manage safety risk while awaiting confirmation.
Ethical considerations
Drug and alcohol testing is not simply about detection. It involves interpretation.
For example:
- oral fluid THC detection typically parallels impairment windows of approximately 7–12 hours when smoked or vaped
- urine detection windows vary significantly and may reflect historic use rather than current impairment
- some medications can produce metabolites consistent with legitimate prescriptions
- dehydration or specimen integrity issues can affect concentration levels.
Professional toxicological interpretation examines context, timing, declared medications and specimen validity before conclusions are drawn. Our team can determine between varying positive drug test scenarios.
Acting without this expertise risks punishing lawful medication use or misinterpreting historical exposure as current impairment.
When termination may be considered
Termination may become appropriate when:
- a confirmed positive result is received
- the finding is inconsistent with declared medication
- the policy clearly states consequences
- the employee has been afforded procedural fairness
- the breach represents serious misconduct, such as deliberate deception or tampering.
Even then, decisions should align strictly with documented policy and be supported by expert interpretation.
The role of accredited testing services
Accredited Australian workplace drug testing services operate under NATA accreditation and the relevant Australian standards. This includes:
- reconciliation of screening and confirmation results
- documented quality control and quality assurance processes
- secure chain of custody
- professional toxicology review
- restricted communication of results to authorised persons only.
Before terminating after a non-negative, ensure your decision is supported by confirmation testing, professional interpretation and a policy that withstands scrutiny. Instead of asking, “Should we terminate after a non-negative?” the better question is: “Have we followed the standard, our policy and obtained expert interpretation before making a decision?”