DOT drug tests really aren’t different than any other kind of drug test. I hear from a fair number of people who have to take them, worried that they’re harder to pass. But the only thing that makes them different is the fact that the requirements for a DOT drug test are set at the federal level.
What Is A DOT Drug Test?
For those who may not know, DOT stands for ‘Department of Transportation’. People who have to take a DOT drug test include anyone who drives a large truck or bus for a living, and any workers who are remotely involved with those vehicles – which is basically anyone in the same company.
A federal agency called the Federal Motor Carrier Safety Administration (FMCSA) has about a hundred pages of regulations that both employers and labs have to follow when administering DOT drug tests. But fortunately, most of those regulations cover details about the paperwork that has to be done. The drug tests themselves are basically carried out just like they are for any other employer. Which doesn’t mean you shouldn’t take them seriously – it just means that you don’t have any extra cause for concern just because you’re taking a DOT drug test as opposed to any other kind.
Does The Dilution Method Work For DOT Drug Tests?
Since the FMCSA requires that a DOT drug test be a urinalysis, then yes, dilution will work fine. At least, it will be if you happen to be a pot smoker.
You’ll be given a standard 5-panel test that looks for other toxins as well, so if you do more than just smoke pot you’ll need to be aware of their detection periods and plan accordingly. For most other drugs besides weed, detection periods are measured in days, not weeks. THC cannabanoids are kind of in a class by themselves because of the way they’re stored in the body (in your fat cells), which is why marijuana use can be detected so much longer than other drugs.
What’s The Best Way To Pass A DOT Drug Test?
Federal regulations require that a lab tech observes you while you’re giving your specimen, so substitution is pretty much impossible, whether it’s a powdered urine kit or a friend’s clean pee. And you should definitely never even attempt to use synthetic urine, just because labs have too many ways to detect that now.
So if substitution isn’t an option (it isn’t for most people, in any situation), that leaves dilution as your only real option. But it’s what I generally recommend to anyone taking a piss test anyway, because when you do it right you’re genuinely able to give a clean specimen right on the spot, without all the stress of trying to use substitution without getting caught.
In any situation where you know your test will be unsupervised, substitution (with something besides synthetic urine) is a guaranteed pass, so in that case you should go for it. But in the case of a DOT drug test, or anytime you think you’ll be observed, dilution is a really close second as far as reliability goes.




July 5th, 2009 at 6:54 am
DOT tests only use GC/MS if the initial test at 50ng/ml is positive. The difference is they also do the initial test at a lab. Only if that is positive is the split specimen sent to a second lab for GC/MS testing. I took a DOT test this past Monday morning and haven’t heard from an MRO yet (that’s good!). It is now the following Sunday morning.
July 6th, 2009 at 1:09 pm
I PASSED! My boss told me this morning the results came back negative. THANKS DEE!!
Regarding my previous comment, this is verbatim from FMCSA Title 49 Part 40 (the law):
§ 40.87 What are the cutoff concentrations for initial and confirmation tests?
(a) As a laboratory, you must use the cutoff concentrations displayed in the following table for initial and confirmation drug tests. All cutoff concentrations are expressed in nanograms per milliliter (ng/mL). The table follows:
Type of Drug or Metabolite – (1) Marijuana metabolites
(i) Delta-9-tetrahydrocannabinol-9-carboxylic acid (THC)
Initial Test 50
Confirmation Test 15
(b) On an initial drug test, you must report a result below the cutoff concentration as negative. If the result is at or above the cutoff concentration, you must conduct a confirmation test.
(c) On a confirmation drug test, you must report a result below the cutoff concentration as negative and a result at or above the cutoff concentration as confirmed positive.
(d) You must report quantitative values for morphine or codeine at 15,000 ng/mL or above.
July 6th, 2009 at 2:48 pm
Brian, that is AWESOME that you passed your test, thanks for letting me know!!! You made my day. :-)
And I also owe you a huge thank you for the great info on FMCSA regulations, you can be sure I’ll add it to my e-book to help out other folks who have to take DOT tests.