Can you drink coffee before a drug test?

Getting drug tested can be stressful even for someone that doesn't use drugs. There are a lot of myths and horror stories out there about people who fail a drug test due to unforeseen circumstances that could have been prevented.

I had a family member who was taking a drug test before being able to get his CDL license. Although this person had never used a drug a day in his life he was still stressing out about it. Telling me that there were people that failed the test because they had taken cough syrup the day before among a bunch of other weird (and kind of not believable) stuff.

Coffee is actually a fairly common subject in the drug testing world, so let's take a deeper dive to see if you should be having a cup before you have to get one done.

Drug Tests

drug test form

To get into this topic with all the necessary knowledge we need to know a little bit about drug tests. The most common one, and the one you're probably worried about, is the urine test.

This is where you urinate in a cup and the tests are either given instantly on the side or sent off to a lab to be analyzed. The most common is the 5-panel screen that tests for THC, Cocaine, Opiates, PCP, and Amphetamines.

Saliva drug testing works by taking a swap in your mouth, usually near the back, and seeing if you have taken any drugs. This is usually used for more recent ingestion of substances and is a bit less accurate though.

There is also blood testing which can test for all of these drugs as well but has different lengths for how long it stays in your system.

Of course, there are hair follicles. They pluck out a bit of your hair and ship it away to be looked at. These are very accurate and can show drugs as far back as 90 days and much more if you have long hair.

False Positives

There have been all sorts of crazy tales about false positives on drug tests. And with how much it costs to drug test personnel these days if you end up with a false positive an employer may be more than a little reluctant to have you take the test again. They'll just pass you off and go for the next applicant in line.

Coffee used to be a big concern for this because in the 80s-90s it actually did cause a problem by creating false positives for methamphetamines. But here in the present, this is not a concern for would-be testers.

Modern drug tests are much more accurate than what we used to have. The normal test you are going to take is a 5-panel screening like the one we mentioned above. These can definitely tell the difference between the caffeine in your urine, blood or hair and any kind of controlled substance.

Coffee's Effect On Urine Tests

Coffee does have an impact on urine tests but not in the way of lighting up a bunch of positives on the panel. What it can do is dilute your urine to the point that it is no longer viable to be tested.

A dilute drug test basically means that there is a lot of stuff in your urine that is not filled with enough of the molecules they are looking for to determine if you have been using drugs.

This can result in either a dilute positive test or a dilute negative test. If you have a dilute positive, dilute positives only happen when you are actually positive for drugs. But dilute negatives, on the other hand, mean that there was no drug found in your system but they can't be 100% sure because it was such a small sample.

Coffee impacts this because it is a diuretic. Meaning it makes you create more urine and therefore can cause a dilute negative. It is not really a big deal and employers will just ask you to retake the test.

Just to put yourself at ease though, you have to drink a pretty large amount of coffee and water to have an impact. If you just have a cup of coffee in the morning before your drug test you are most likely going to be just fine.

Coffee's Effect On Saliva Tests

getting some saliva for test

The saliva test is used as a spontaneous drug test. There is usually little time to prepare and the results are given within minutes of taking the test as they just plop it in a solution to see the results.

Coffee does seem to have an effect on saliva tests in the form of a false positive for four out of the five most common drugs tested. This does not mean you shouldn't drink your coffee though.

The only reason this should happen is if the person doing the test does not follow the manufacturer's guidelines. And these tests are so inexpensive that they'll likely just test you again if you protest a false positive. This is just something to keep in mind should this actually happen to you.

Coffee's Effect On Blood Tests

If you are getting blood work done you may have been told to not eat or drink for some amount of time before the test. This is only because certain tests are going to look at substances in your body that are affected by food and drink.

This does not apply to a drug test performed through the blood. Which makes this pretty cut and dry, coffee should have absolutely no impact on the results of this sort of drug test.

Coffee's Effect On Hair Follicle Tests

Coffee also has a few stories surrounding your hair. Some people even claim that caffeine enriched shampoo will promote hair growth. As such it is normal to wonder if it will have an effect on hair follicles for a drug test.

This once again is very clear. No. Coffee will have absolutely no bearing on your hair follicle test. The caffeine will without a doubt show up but these tests are so accurate now that they'll be able to distinguish when, within reason, you took the drug not just if you took it at all.