Types of drug tests and standards

The drug tests a client participates in must comply with the Australian/New Zealand standard - AS/NZS 4308:2008 (the drug test standard).

Drug testing detects residues of certain drugs and their metabolites in the body. Each drug has a set threshold or cut-off level for screening and evidential drug tests. To fail a test a person must have drugs present in their system that reach these thresholds or cut out levels.

There are two types of tests that measure the presence of drugs, these are:

• a screening test which shows whether drugs are or are not present
• an evidential test which is completed by an accredited laboratory, which can identify the actual drugs, the drug family and the amount of drugs present

In order to test, a urine sample must be provided by the person. Urine testing is the most common and accepted form of drug testing, and meets the drug test standard. To meet the drug test standard drug tests are undertaken by a person who is NZQA accredited for urine specimen collection in the workplace.

The standard requires the collection of a sample to follow a process that minimises the chances of a person being able to affect the result of the sample through substitution or adulteration.

Most employers and training providers will use a screening test as this provides them with enough information to help make the decision to employ a person or not.

Screening tests are usually done using on-site urine tests as they provide a simple and cheaper method of detecting a wide range of drugs and can be undertaken outside of a laboratory.

Screening tests detect the presence or absence of specific drugs and drug test providers advise that they are up to 98% accurate. Very occasionally they can produce false results, this is usually because:

• they have detected some prescribed medicines or
• the level of a drug in a person's system is near to the threshold or cut-off points for a particular drug

Some employers, particularly larger employers, may require an evidential test and will not conduct screening tests or they may conduct both tests.

Generally, evidential tests are used when a screening test is failed.

Evidential tests are a more comprehensive and expensive method of detecting drugs. They can detect a wider range of substances and identify the specific substance. This test is also referred to as a confirmation test.

Evidential testing is conducted in an accredited laboratory by qualified staff. Samples are sent to the laboratory by drug test providers or specialised staff, or the laboratory will arrange to take the sample themselves.

For more information see:

• Client fails the screening drug test
• Effect of certain drugs