Frequently Asked Questions

Find the answers to all your workplace health and safety questions.

Depending on the person, including (but not limited to) height, weight, sex, the type of drug and how it was taken, the length of time a drug can remain in your system varies greatly.

If using an oral fluid device to detect drugs, the detection window is measured in hours, typically 4 – 24 hours. In most cases, drugs can be detected in urine between 48 – 72 hours. For long-term use of cannabis, THC can be detected up to several months at the time of the test.

Hair testing will detect repeated use over a period typically measured in months. A standard test covers 3 months. One centimetre of hair detects about one month of drug use.

Breath alcohol will typically provide a positive result for hours, depending on the intake volume and timeframe.

Drug and alcohol screening is legal. However, you still need to consent for the sample to be taken and for results to be provided to your employer.

Check your company’s drug and alcohol policy about what may happen if you refuse a drug and alcohol test. For example, many companies consider a refusal to undergo a drug and alcohol test a positive test, resulting in relevant disciplinary action.

It depends very much on the medication you are taking. For instance, codeine can cause a non-negative screening result for opiates (the class of drugs that includes heroin). However, all non-negative screening results are transported to our toxicology laboratories for confirmation. Any medication you are taking, including vitamins and supplements, should be declared at the time of the test. Our scientists can determine if the laboratory result is consistent with your declared medication.


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