work drug tests

[jakoz]

Something I was just thinking about, from something I remember reading...

From the
Drug Testing Methods FAQ:

Tests performed and 'positive' levels
There are two main tests performed: the immunoassay, and the GC-MS test (Gas Chromatography - Mass Spectrometry). Other tests such as Thin Layer Chromatography (TLC) are used but they are relatively rare. Typically, an immunoassay is first used on a sample. If the substances they are looking for are above a certain level, a GC-MS is called for. If those substances are above another level on the GC-MS, you have a positive test for that substance.

Now I cant find more info, but I thought I remembered reading that a fairly high percentage of positives to the first test are false, and (now it gets worrying) that the labs do not *have to* send the sample for confirmation with the GC-MS test, and that many often dont to cut costs.

I hope that they would not be that reckless, or that there would be legislation against it... can anyone confirm or deny this? Also of interest: if this was true, you could probably demand a retest if you could prove that they skipped the GC-MS, even if it was a real positive.

 

[phase_dancer]

This is from a Uni friend who works as an analytical chemist. We have just completed a collaborative project on drug analyses and her part was workplace testing. Here are some selected extracts from B's report on the Qld mining industry

It has been identified that both illicit and recreational substance abuse impact negatively upon almost all industries in Australia. (Wall 1992) In a recent report titled “The contentious issue of Drug Testing in the workplace: The case of the South Blackwater Mine”, Peter Holland conservatively estimates that substance abuse in Australia:

• 
  
  [*]Imposes direct costs on industry (predominantly in lost productivity) accounting to some $3.7 billion annually
  [*]Imposes indirect costs to industry of $10 billion annually (e.g. Employee turnover, poor decision making, employee stress)
  [*]Accounts for 10% of workplace deaths and 25% of accidents

Under occupational health and safety legislation there is an obligation upon employers to provide a safe place of work for all employees and visitors to their site. (Holland, 2002)

Companies are putting in place Work Safe and Fitness for Work Policies protect the Occupational Health and Safety of their workers. Fitness for Work for an individual includes that he or she is physically and mentally fit to perform work and without them being impaired by the influence of alcohol or drugs. (QCL draft Fitness for Work Policy, A. Gardner 2003) Included in Work Safe and Fitness for work policies is the need for a workplace drug-testing regime.

Procedures for testing for drugs of abuse and recreational drugs are included. In Australia the only method of drug testing that is nationally recognised is the analysis of Urine samples as set out in the Australian and New Zealand Standard AS/NZS 4305:2001.

This standard sets out procedures for the sample collection and the detection and quantitation of drugs of abuse in human urine. The method is intended for workplace, medicolegal or court directed detection of any or all of the following classes of drugs: (AS/NZS 4308:2001)


a) Opiates
b) Sympathomimetic amines
c) Cannabis metabolites
d) Cocaine metabolites
e) Benzodiazepines


Aspects of this standard have relevance to testing for drugs of abuse in urine, the collection, necessary precautions, procedures relating to dispatch, transport and storage of samples, and the approved methods of analysis. The testing laboratory must be a NATA AS 4308 accredited laboratory.
The approved methods for the preliminary testing of samples as stated in the Standard are as follows:

• 
  
  [*]Gas Chromatography (GC)
  [*]Gas Chromatography/Mass Spectrometry (GC/MS)
  [*]High Pressure Liquid Chromatography (HPLC)
  [*]Immunoassay
  [*]Liquid Chromatography/Mass Spectrometry (LC/MS)
  

The preliminary results are then compared with the tables of cut of values given in the standard. (There are different tables for Immunoassay and Non-Immunoassay initial tests.) If the results returned are greater than or equal to the given values then confirmatory testing is required before any results can be issued. If the results are less than the values given in the tables then the result is reported as “not detected”. (AS/NZS 4308:2001)
It is stated in the standard that laboratories that perform the initial testing shall also perform the confirmatory tests. GC/MS is the only recommended confirmation method for cocaine metabolites, cannabis metabolites, opiates, sympathomimetic amines and benzodiazepines. (AS/NZS 4308:2001)
However it is also noted that LC/MS, LC/MS/MS and GC/MS/MS systems may be substituted provided all the criteria for the acceptance of results listed in clause 5.9 of the standard are satisfied.

 

[phase_dancer]

Sorry e-bay, I forgot to address your questions:

How does it work where sudafed can give you a false positive?

When drugs are metabolised, the body's first priority is usually to make them more water soluble, in an attempt to get rid of them asap.

As you probably realise, pseudo and meth are chemically very similar. Pseudo is basically meth with an OH on the carbon next to the benzene ring. Depending upon things such as enzyme availability, metabolism rates, other substances in the body, general health etc. your body may choose one or more of several routes to end up with any one of, or a combination of the three desired, easily excetable metabolites. (ring hydroxylated products)

Sometimes pseudoephedrine can have it's original OH "knocked off" but only after hydroxylation of the ring, and sometimes Meth/Amp can have a OH stuck on to the first carbon to make it ephedrine. I won't go into details of this or the other important enzyme action to this known as demethylation, except to say that meth can become amphetamine and pseudo can become PPA. MDMA can have it's methylenedioxy group removed (demethylenation) and follow the same paths i.e. come up as a amphetamine/pseudo metabolite.

In short, the routes and products are many and some are the same for both drugs. I've currently un-installed chem office to prepare for reformatting, otherwise I'd draw you some nice pictures, but sometime in the future I intend to prepare something which discusses all this with nice pretty pictures.

Can you say you had some of them and by the time they retest you you're clean?

I'm not sure about this. It is the immunoassay tests which are known for false positives, as these use an antibody which binds to the metabolite substrate, and as mentioned this can be the same for pseudo and meth. I'm sure it has been used in the past as an excuse, but with recent restricting of the availability of pseudoephedrine, any legit pseudo you source is now recorded. Records shouldn't be available to employers, but I bet some time in the foreseeable future they will be....anyone for a wager?

Will the increased sensitivity of these tests also increase the accuracy of molecule identification so sudafed will not give you a false reading?

Other than immono tests, the most commonly used and often the only one approved (see above) is GC or gas chromatography. Different forms of chromatography (used to separate components in a mixture) have difficulty in separating certain mixtures of compounds. GC, often requires derivatives to be made of the compounds prior to running the analysis. If there was a false positive for pseudo with immuno tests, further testing by GC/MS looking at ratios of metabolites etc, should be able to distinguish meth from pseudo, but I'm not sure on this.


Something else to make you cringe:

Recently, a technique for producing a derivative of LSD has been employed in LC/MS (LC=liquid chromatography, MS = mass spectroscopy) Used in conjunction with a fluorescence detector, and the previously impossible to test LSD in urine is now childs play for the analyst, who can find the tiniest amount present as less than 1% in urine, some 24 hours after ingestion 8(

 

[ebay]

Just when I thought a couple of vintage sudafeds would prove more valuable to me than I ever thought possible you bring up acid! Man, why won't these people just smoke some dope and easy up on the "advance the drug test dude" movement? It's enough to make me wanna quit, almost.