It’s common knowledge that secondhand smoke has its consequences. No wonder smoking is prohibited indoors around the world.
But what happens when it comes to being around marijuana smokers? On top of that, what happens if you’re around secondhand weed smoke and you have a drug test coming up?
Believe it or not, this type of exposure can put you at risk, but the conditions have to be just right (or just wrong) for that to happen.
So, let’s talk about the effects of secondhand smoke on THC tests, and what you can do to make sure you avoid testing positive.
A Short THC Testing Recap
Before we get into it, let’s quickly look at how testing for THC is conducted and what is actually being tested. This will help us understand how secondhand marijuana smoke exposure affects test results.
First off, it’s important to note that both lab and at-home tests (like the Exploro THC test) do not test for the presence of the THC compound itself. In fact, these tests detect metabolites (THC-COOH) that our body produces in response to THC.
These metabolites are detected at a cutoff level, most commonly from a urine sample. In simple terms, if the presence of metabolites is under the cutoff level, the test comes back negative, and vice versa.
How is THC tested?
Whether you have employment drug testing coming up, you’re tracking your detox, or you’re doing a regular checkup, the most frequent type of testing is from a urine sample.
If we’re talking about at-work THC testing, a dedicated, certified testing crew will come to your place of work and collect the samples (which you provide privately, of course).
The samples can be tested at a higher cutoff level (50 ng/ml) on the spot, using test strips. If this comes back positive, the sample is then sent to the lab for a confirmatory test at a stricter cutoff of 15 ng/ml.
Now, besides urine testing (which is the most common type), THC can be detected via blood, oral (saliva), and hair samples. Blood and saliva tests can detect recent exposure, while hair tests do not detect secondhand exposure, as they’re designed to detect prolonged use.
Marijuana Exposure – Not All Secondhand Smoke is the Same
Let’s get one thing straight right away – failing a THC drug test from being exposed to secondhand smoke is highly unlikely, but not impossible. Here’s the gist of it.
For non-smokers who get exposed to secondhand marijuana smoke occasionally, the risks of failing a drug test are virtually zero. Especially if we’re talking about an outside setting. Even if you somehow get around a lot of smoke, but are still in a ventilated area, you don’t have to worry. Here’s a quick list of similar scenarios that won’t lead to a positive drug result:
- Brief indoor exposure
- All kinds of outdoor exposure
- Living with a marijuana smoker in a ventilated space
- Being around friends who smoke
- Smelling the cannabis smell (this gets people into a panic, but there’s no grounds for that)
The thing is, in cases of passive exposure, any THC-COOH formed is usually present at very low levels and typically falls below testing cutoffs within hours to a day.
Who is at risk the most?
Now, we mentioned that the chances of failing a test from secondhand smoke are near-zero, but not zero. Here’s a list of conditions that (together) can lead to THC-COOH detection from secondhand exposure:
- Being in small, unventilated rooms with smokers (hotboxing)
- Having more than one active user around you
- Being exposed to smoke for prolonged periods (longer than 1 hour)
- Frequent secondhand marijuana exposure (every few days or so)
So, just to reiterate, to get a positive drug test result, a combination of several of these conditions significantly increases the risk of a positive result. Even then, the chances are not that great, but if you have a zero-risk attitude, try to avoid these situations prior to being tested.
People who do not smoke (or ingest) THC reach significant levels of metabolites extremely rarely. But if you’re exposed to smoke regularly, in small, unventilated spaces, for hours at a time, these metabolites may find a way to store up in your body fat, since they’re fat-soluble. This may lead to a positive THC drug test result.
At that point, exposure levels may be comparable to light active use.
Why Cutoff Levels Prevent False Positives
There’s a reason why screening tests are done at a higher, and confirmatory tests at a lower (stricter) cutoff level.
A person exposed to secondhand smoke will get rid of the metabolites in a few hours. The liver is quite efficient with this task. So, even if a screening test confirms the presence of THC-COOH, the confirmatory test will almost always come back negative.
In fact, the tests are designed with this type of exposure in mind. THC users will have metabolites stored up in their body fats in quantities that the liver cannot process quickly enough.
Secondhand Smoke Can Make You Fail A THC Test. Will it? Not Likely
So, to put your mind at ease, the likelihood of failing a drug test from secondhand smoke exposure is really, really small. But, if you know you have a test coming up, make sure not to spend too much time with smokers in confined, poorly-ventilated rooms.
And, even if the initial screening test somehow comes back positive, by the time the confirmatory test results come back, it will most likely be negative.