Are Home THC Drug Tests Accurate?

Are Home THC Drug Tests Accurate?

Published on 9/14/21

So, you just found out you have a drug test for cannabis coming up and you've been trying to drink as much water and detox drinks as possible. You also buy a home drug test from the store, give it a try, and test negative. The big question now: is your home drug test accurate? Let's take a deep dive into how cannabis stays in the system, how your body processes it and how to detox for a drug test. 

How Long Does Cannabis Stay in Your System?


Marijuana is comprised of over 400 chemical compounds, all of which work together to provide specific benefits and effects. Of those 400 compounds, over 100 are cannabinoids, including the most popular and one of the plants most prolific: THC (tetrahydrocannabinol). When you take a drug test, THC is what will trigger a "positive" result for marijuana usage. When consumed, THC is absorbed into the bloodstream and dispersed throughout the body. As a lipid-soluble chemical, THC binds to fat within your body, which increases its durability and the time it takes to be fully broken down and eliminated. How long THC remains in your system depends on a variety of factors.

Marijuana Usage

The more frequently you use marijuana, the longer marijuana will likely stay in your systems. 

  • First-time or infrequent users: THC is likely detectable for up to three days. 
  • Casual users (3-4 times a week): THC is likely detectable for 5 to 7 days, but may remain detectable up through two or three weeks.
  • Heavy users (every day): THC is likely detectable for up to 30 days or more.


Just as the frequency of usage affects the detection window, so does the dosage of marijuana consumed. If the last time you smoked marijuana involved a large dosage, even if you are an infrequent user, it will stay in your body longer. The more you consume, the more THC there is to bind with body fats and be dispersed throughout the body.


Your body's natural metabolism (the same thing that determines how fast you break down nutrients from foods) will have an impact on how fast it breaks down THC. The faster your metabolism, the quicker THC should be eliminated from your system. People naturally have a wide range of metabolism levels, but metabolism can be trained to increase over time through exercise. The more your body works, the quicker it breaks down nutrients and chemicals like THC. 

Body Fat Percentage

Because THC binds to fats to remain in the body longer, a person's body fat percentage can have a big impact on how long THC remains in the body. Higher body fat percentages mean there are more lipids for THC concentrations to bind with, and vice versa. 


If you are dehydrated, THC concentration increases within your body. So, if you're looking for how to pass a drug test for weed with minimal effort, just drink lots of water. It's not guaranteed to increase the breakdown process, but there is a chance it could help speed it up. 

What Types of Drug Tests are There?

Different types of drug tests collect traces of THC in different ways, each of which has different detection windows.

Urine Testing

If you found this article by typing in "pass urine test," you're probably not alone. This is the most common type of drug test, especially for employment purposes, and has the general detection windows discussed above based on usage frequency:

  • First-time or infrequent users: THC is likely detectable for up to three days. 
  • Casual users (3-4 times a week): THC is likely detectable for 5 to 7 days, but may remain detectable up through two or three weeks.
  • Heavy users (every day): THC is likely detectable for up to 30 days or more.

Saliva Testing

Most commonly used for roadside testing (in cases of a potential DUI), saliva testing has a similar detection window as urine testing, with infrequent users remaining positive for up to three days and heavy users up to 30 days. 

Blood Testing

THC usually only remains in the blood for up to three days, but it may take up to 25 days for chronic users to lose all traces of it within their blood. This method is most commonly used in laboratory settings. 

Hair Testing

When consumed, trace amounts of THC are collected within your hair follicles and remain there for up to 90 days, regardless of frequency. However, hair testing is a very uncommon method. 

Are At Home Drug Tests Accurate?

At-home drug tests have become much more accurate over the last few years; and while they aren't as accurate as professional lab tests that you'll receive during a work-related drug screening, many at-home tests boast up to 99% accuracy. There are several different types of tests. Most are urine-based. Some work like a pregnancy test, showing positive or negative without having to send results in. However, there are also tests you can send to a lab for more accurate results; of course, send-away tests can take up to several days to get results back. While these tests are fairly reliable, it is important to note that no test is 100% accurate - there is always a chance that your test is reading incorrectly.

How to Detox for a Drug Test


First and foremost, there are claims out there for how to clean out your system in 24 hours,  these claims are false and can sometimes be potentially hazardous to your health. Cleaning your system is not an overnight process and passing a drug test naturally by abstaining from weed is your best course of action. Here are, however, a few quick options you might pursue if you're looking for the safest, fastest way to clean out your system for a drug test:

Exercise and Healthy Diet

Eating right and exercising will, over time, increase your metabolism. In turn, a faster metabolism means your body will break down THC quicker.

Detox Drinks & Detox Kits

 If you're wondering "do detox drinks work," the answer is good and bad. Yes, detox drinks and kits might help get THC out of your system quicker, but they usually work over one or two weeks. 

Drink Water

The more hydrated you are, the quicker your body will flush out THC. Drinking a ton of water isn't going to get THC out of your system within a few days if you're a heavy user, but it might help quicken the processes over a few weeks. 

Do you have experience with at-home drug tests or clearing your system of THC? Let us know your tips and tricks in the comments below!

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