• illegal drugs; those prohibited from manufacture, sale or possession in Australia, for example, Cannabis, cocaine, heroin and ecstasy
• misuse, non-medical or extra-medical use of pharmaceuticals; drugs available from a pharmacy, over-the-counter or prescription, subject to misuse (opioid-based pain medications, opioid substitution therapies, benzodiazepines, over-the-counter codeine and steroids)
• other psychoactive substances; legal or illegal, used in a harmful way (kava, inhalants such as petrol, paint or glue [not tobacco or alcohol]).
Most employers, insurance companies, government agencies, etc., in the United States (US) and other jurisdictions, will ask for a urine test, the industry standard for workplace drug testing, and the only method approved for US federally mandated drug tests. A test for Cannabis is looking for a metabolite (chemical produced by the body from another chemical taken in by the body) of ∆9-tetrahydrocannabinol (THC), one of the main cannabinoids in the herb, Cannabis sativa L. Urine is used to test for the amount of just one of the metabolites of THC. The metabolite they are looking for in urine is THC COOH (carboxy-THC or 11-nor-∆9-tetrahydrocannabinol-9-carboxylic acid).
Following Cannabis use via smoking, vaporising and other inhalation means, THC is rapidly absorbed and distributed into body fat. A 2001 study, 'The Forensic Pharmacology of Drugs of Abuse', out of the UK reported approximately 20% of THC is excreted in urine and 40% in faeces. THC is found in blood, oral fluid, hair and sweat; 11-hydroxy-THC is also found in blood, while THC COOH is the main urinary metabolite.
In the body, THC is primarily metabolised in the liver where the hepatic cytochrome P450 enzyme oxidises THC to the active metabolite 11-hydroxy-Δ9-tetrahydrocannabinol (11-hydroxy-THC). This is then oxidised to the inactive 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and the conjugated THCCOOH-glucuronide. A number of other minor metabolites are also formed, including the active 8β-hydroxy-Δ9-THC and inactive 8α-hydroxy-Δ9-THC and 8α,11-dihydroxy-Δ9-THC. THC-COOH and 11-hydroxy-THC are most important for biological sample testing procedures.
|United Kingdom Wolff Report|
World’s best practice would abandon the ideology of the war on drugs in favour of measures for genuine road safety. It would give us tests that can identify all the drugs of concern, tests that do not produce numerous false positives and tests that measure the actual driving impairment of those being tested. Until random drug tests achieve that minimum level of practicality and justice, the public should be wary of the motives of the politicians pushing them.
- AS/NZS 4308:2008 Procedures for specimen collection and the detection and quantitation of drugs of abuse in urine
- AS 4760:2006 Procedures for specimen collection and the detection and quantitation of drugs of abuse in oral fluid
- sample collection;
- screening test;
- confirmatory testing.
- There are no prescribed cut-off concentrations for screening devices or set quality control limits as there are for urine screening devices as detailed in Appendix A of AS/NZS 4308:2008.
- The target concentrations for screening devices ... are described as “nominated” in Section 1.5. This Section also states that “there is yet to be an accepted cut-off concentration” and that “concentrations higher than the initial testing target concentrations may sometimes be used if sensitivity is the limiting factor but this reduces the ability to detect drug use”. Accordingly, a facility may nominate its own targets (but not lower than those used for confirmatory testing). Where the nominated targets are set higher ... by the facility due to the insensitivity of a screening device, false negative results may result, despite compliance with the Standard. This would be a key concern for both drug screening programs and the public.
- The ability to test for drugs with known instability in saliva post collection, especially tetrahydrocannabinol (THC), is compounded by the allowance of “nominated” targets. The allowance of nominated screening concentrations at levels at or above the confirmatory concentrations may impact on the ability of confirmatory testing to reproduce a non-negative screening result due to loss of drug during transport and handling.
- There are no acceptance criteria for what constitutes acceptable verification of screening devices as there are for urine screening devices as detailed published in Appendix B of AS/NZS 4308:2008.
- The Standard requires quality control (QC) to be run. However, it is noted that the negative QC is defined as a drug free specimen. Such a specimen does not test the sensitivity of a device to identify donor samples which contain drugs at a concentration below the nominated target cut-offs. This is inconsistent with Appendix A of AS/NZS 4308:2008 which requires the below cut-off QC to be at a concentration between 25-50% below the cut-off concentration. The positive control is at or within 50% above the nominated concentrations. This is also inconsistent with AS/NZS 4308:2008 which requires the positive control to be between 25-50% above the cut-off concentrations.
The best way to deal with Cannabis on the roads in Australia is to legalise, and to gauge the effect Cannabis legalisation can have on the roads, we need only look at what has happened since legalisation took effect in Colorado, US. A month-by-month comparison of highway fatalities in Colorado through half of 2015 and 2014 along with highest fatality figures for each month since 2002, the lowest for each month since 2002 and the average for each month since 2002. If Australian governments were serious about reducing deaths on the roads they would stop doing the same things over and over and expecting different results. We all know that is the definition of insanity. Let's reduce the road carnage, dispense with testing for Cannabis and relegalise it!