How Accurate are At-Home Drug Tests Compared to Lab Tests?

Drug Test, Marijuana


No test is 100% accurate, including at-home drug tests. However, ​​according to the United States Food and Drug Administration, these home test kits are extremely sensitive to drugs in a urine sample. This means, that if drugs are present, it's possible to get a preliminary (or presumptive) positive test result. If the preliminary result is positive, you should send the urine sample to the lab for a second test.

A positive drug test might result in the loss of work, even if you live in a state where marijuana is legal and use cannabis on your days off. Apart from government professions, personnel in the healthcare, transportation, and manufacturing industries also get tested.

If you have an upcoming drug test and aren't sure if you'll pass, you might want to try an at-home drug test first. You can find these kits at drug stores and online for an affordable price, and you’ll get results in just minutes.


In this article we'll answer these questions:


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Are Home Drug Tests Accurate?

Woman's Hand Showing Sealed Pouch With A Highly Sensitive THC Urine Drug Test Strip Inside On The Table

The Exploro® at-home urine THC test has been proven to give a 99 percent accurate result when used according to the instructions (included in each box). 

Nonetheless, according to the FDA, a variety of factors can influence the accuracy of home drug tests, including (but not limited to): 

  • How you perform the test.
  • How you store the test or urine.
  • What you eat or drink before taking the test. 
  • Any prescription or over-the-counter drugs you take before the test.

Because of these issues above, a home drug test can only be deemed 99 percent accurate. Plus, if you get a positive drug test result, your employer will probably ask you to get retested by a professional lab. 

Plus, eating and drinking certain foods and medications can also trigger a false positive. On the other hand, a false negative might result from an expired test, incorrect storage, or taking the test too soon or too late.

"Window of Accuracy" You Should Consider When Taking a Drug Test

Depending on the drug you’re testing for, be it THC, Cocaine, Amphetamine, or other common illicit drugs, your usage habits, lifestyle, and metabolism all play a role. Below you’ll find times of how soon a drug can be detected on a test after ingesting it. 


Amount of time it takes for a test to be positive after taking this drug

Amount of time a test will continue showing a positive result after taking the drug once (except for heavy users)


1-3 hours

1-7 days

Crack (Cocaine)

2-6 hours

2-3 days

Heroin (Opiates)

2-6 hours

1-3 days


(Amphetamine, methamphetamine)

4-6 hours

2-3 days

Angel Dust/PCP

4-6 hours

7-14 days


2 to 7 hours

2 - 4 days


2 -7 hours

1 - 4 days


2 - 4 hours

1 - 3 weeks


3 - 8 hours

1 - 3 days

Tricyclic Antidepressants

8 - 12 hours

2 - 7 days


1 - 3 hours

1 - 2 days


Keep in mind that THC metabolites from marijuana can be detectable for up to 90 days in heavy, daily users, so use these values only as a guideline. Your lifestyle and body fat percentage will also influence the rate at which THC metabolites leave your system. This is due to the fact that they are stored in your fat cells and released over time.

How Do Home Drug Tests Compare to Lab Tests?

As I mentioned before, no test can be considered 100% accurate, including lab tests. However, a laboratory screening involves the use of sophisticated equipment, which results in significantly fewer false positives. 

A recent study at News Medical Life Science supports the accuracy of at-home tests, comparing self- and clinician-administered rapid tests. They found the results were statistically similar in both sensitivity (83.9% to 88.2%, respectively) and specificity (99.8% to 99.6%, respectively). This suggests physicians can feel confident prescribing treatment based on patient-reported, self-administered test results when positive.

However, since lab tests tend to be pricier and results take longer to come back (on average 24-48 hours), an employer will most likely request this only after an initial screening comes back positive. 

Despite the constraint of time, professionals conduct lab tests in ideal environments compared to home drug tests. The reason is, that when you go to a lab to take a test, both your urine and the test are stored at appropriate temperatures.

Whereas your at-home drug test can be damaged during delivery by hot weather, careless handling, etc. Of course, choosing a reliable seller like Exploro® will result in either a full refund or a new product delivered to you.

Finally, home test results won’t hold up in court due to the lack of components considered in court when ruling out a drug test result. This can be due to cutoff levels, factors that influence a positive result (like secondhand smoking), and more.

If You Pass a Home Drug Test, Will You Pass a Lab Test?

A Bottle With a Urine Sample in the Laboratory on a Desk and Laboratory Worker in the Background

It’s debatable. The reason is, it's not a given that if you fail a home drug test, you'll also fail a lab test. According to a 2010 paper given at the American Psychiatric Association's annual meeting, 5-10% of lab tests may disclose false positives. Approximately 10-15% of the time, false negatives may occur.

If drugs above the cutoff level are present, a home test kit will be able to show you. It's possible that the amount of a substance it identifies isn't enough to fail a drug test (depending on the cutoff level). A lab test can determine how near you are to the limit. It also provides a pass or fail result.

So, all in all, it boils down to the test's cutoff level, medications or food that could cause a false positive, and other factors.

So, which is better?

The bottom line is that testing performed in a controlled laboratory, by skilled professionals, and using expensive equipment, is more accurate. You just have to be sure that when you pay hundreds of dollars for intricate testing using expensive instruments, you're receiving exactly what you paid for.

When it comes to a home drug test vs. a lab drug test, a home drug test is usually the better option (as long as you do it correctly). First, read the instructions and make sure you understand them completely. Take this first step before collecting your urine sample, as checking it too soon or too late may have an impact on your results. Finally, keep a close eye on the accuracy window for whatever substance you're testing for. 

Any questions? Let us know below, and we’ll answer them!



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so it sounds like both are basically accurate, and it mostly depends on your time window. Interesting read.


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