By introducing “Passive” alcohol testing, organisations can:
- Speed up employee testing (particularly important where zero tolerance sites test every person entering the workplace every day);
- Reduce the use of plastic mouthpieces required for “Standard” alcohol testing, thus reducing cost per test;
- Reduce the environmental impact of the need to dispose of large numbers of single use plastic mouthpieces.
What is Passive Testing?
Passive testing for alcohol is a process where a sample of a subject’s breath is analysed without the use of a mouthpiece or any physical contact. It commonly involves a subject exhaling/blowing/talking within close proximity of an alcohol breath testing device.
The instrument uses an internal pump to draw in a sample of ambient air from around the inlet of the instrument, then analyses that air sample for the presence of any alcohol. Activation of the instrument pump to draw in the sample may be manually instigated by the operator of the instrument, or automatically activated by an internal pressure sensor detecting a flow of air over the instrument inlet.
The Purpose of Passive Testing
Passive testing should not be confused with standard (mouthpiece) testing. The primary purpose of passive testing is to rapidly establish that no alcohol is present. For Police and large workforce organisations, this means motorists or employees can be quickly moved on with minimal disruption and drain on resources. For workplace health and safety, the purpose of passive testing is to establish that no alcohol is present, enabling them to safely commence their shift.
Accuracy vs Sensitivity
An important misconception with passive testing, is that it in any way involves accuracy of the amount of alcohol in a tested subject. It does not! The best quality alcohol breath testers, as used by Police, do not produce an alcohol reading for a passive test. They indicate primarily that no alcohol has been detected, or that alcohol has been detected in or around the instrument at the time a subject is being tested. It is important to note that if alcohol is detected, it does not automatically mean the subject being tested has consumed alcohol.
What is extremely important is that if any alcohol is present in the ambient air surrounding the instrument at the time of the test, then the instrument can detect it. For this reason, it is the sensitivity of the instrument to detect alcohol, not the ability of the instrument to accurately determine the level of alcohol in the subject that is of prime importance. A quality alcohol tester with a passive mode function has the ability to significantly increase the sensitivity for alcohol, thereby ensuring that if alcohol is present at the time of the passive test, regardless of the source of that alcohol, then the instrument will detect it.
Once alcohol is detected, the instrument is ‘flagging’ the need for a further standard (mouthpiece) test to establish if the source of the alcohol is the subject being tested, and if that is the case, an accurate reading of the subject’s blood alcohol reading (BAC) or breath alcohol reading (BrAC). Note: The difference between a BAC and BrAC is simply the unit of measure used to record and display the alcohol reading. Effectively, they mean the same thing.
Will a Passive Test Always Detect the Presence of Alcohol?
If a quality alcohol breath tester, capable of increased sensitivity in passive testing mode is used, and the test is conducted by a well-trained operator in accordance with manufacturer’s instructions, passive tests are very reliable in firstly establishing the subject is totally alcohol free and secondly, detecting the presence of alcohol in the ambient air surrounding the instrument.
Pressure Activated Passive Testing
More recent technological advancements have led to the introduction of “pressure activated passive testing” where the blow pressure of the subject automatically triggers the instrument to take a sample of ambient air, thus increasing the likelihood that the analysis of alcohol will centre on the breath of the subject. However, this does not rule out the above environmental influences that can influence the outcome of a passive test.
A Positive Passive Test for Alcohol – The Next Step
Passive testing in industry situations is a valuable first step towards ensuring a workplace remains alcohol free. However, it is extremely important that industry users of passive testing adopt a similar process to Police. Any passive test that detects the presence of alcohol should result in the following course of action:
- The subject should be required to undergo a supervised withholding period of 15 minutes (nothing but water allowed);
- A second “Active” – also known as “Standard” test for alcohol using a mouthpiece should be conducted on the subject to determine the presence of alcohol in the blood. This test should only be conducted on an Australian Standards Certified AS 3547 instrument. If alcohol is present, an accurate BAC or BrAC reading will be determined;
- If this subsequent standard test produces a zero alcohol reading, it should be assumed that the initial passive test result positive for alcohol was the result of non-alcohol consumption, as outlined earlier.
- Note: Some people refer to such passive test results as false positives. This is generally incorrect. A quality instrument that displays a positive passive test reading has almost always detected alcohol (ethanol), it is simply that this alcohol is not from the subject having consumed alcohol, but from another source.
Passive Mode Sampling Cup
Delivering accelerated breath testing with an economical sampling method the passive mode sampling cup is available for the LE5 and HH4 breathalysers. Features anti-blow-back feature and re-directs breath flow away from the donor and operator to support fast, cost effective and environmentally friendly testing – see product here.