Delta THC | Science

THCa Drug Test: Will I Test Positive?

Dr Abraham Benavides


Dr Abraham Benavides

Medical Doctor

If you consume cannabis, you’re familiar with THC and know it will show up on a drug test. 

What about THCa, though? Will you test positive if you’ve recently consumed THCa products? 

Seeing as THCa is the acidic precursor to THC and doesn’t contain psychoactive effects on its own, will THCa show up on a routine drug screen? 

If you need to pass an upcoming drug screening and you’ve recently consumed THCa products, this article is for you. 

Keep reading to learn more about a THCa drug test, and if you’ll test positive for THC if you have to take one.

thca drug test

Key Takeaways: THCa Drug Test

  • THCa transforms into THC when consumed or heated, and both are eventually broken into the metabolite THC-COOH.
  • Most drug tests screen for THC metabolites including THC-COOH.
  • If you consume THCa it may turn positive on a routine drug test.
  • THCa can be detectable in your system for months.
  • The amount of time THCa remains in your system depends upon multiple factors.

Does THCa Show Up On A Drug Test?

If you consume THCa flower or related products and you take routine drug screens (or plan on taking a drug test soon), you’re likely wondering if the cannabinoid will show up on a drug test. 

The short answer is yes. 

If you’ve consumed THCa, it’s highly likely it will show up on a drug test. 

When THCa goes through the process of decarboxylation, it automatically converts to Delta 9 THC. When D9 is consumed (which is ultimately what happens when you decarb THCa) it converts to THC-COOH, a THC metabolite. 

Considering most drug tests screen for THC metabolites like THC-COOH, THCa will most likely show up on a routine drug screening.

The molecular structure of THCa is almost identical to THC, save for an extra carboxyl group on THCa. That said, you can expect that most drug tests (if not all) will pick up on traces of recently consumed THCa in the system. 

Again, both THC and THCa metabolize into THC-COOH. Scientific reviews of cannabis properties and its derivatives show that THC-COOH is the primary inactive metabolite found in cannabis. It’s also the substance that urine drug screens (UDS) and other drug screenings test for. 

If you’ve consumed decarbed THCa you will get high, and if you take a drug test, you can almost guarantee you’ll test positive for THC.

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So Will THCa Test Positive?

Yes, THCa will very likely test positive on a drug test.

Since THCa is eventually converted into THC-COOH by the liver (and drug testing kits screen for THC-COOH), consuming it will most likely result in a positive drug test. 

Even though the sensitivity of drug tests vary, all drug tests look for THC metabolites. The main detectable metabolite is THC-COOH.

Some screenings can detect THC metabolites for a week or two, while more sensitive screens can detect trace compounds for up to two months. It all depends on the sensitivity (cut-off) of the test, what specific compounds the test looks for, and the specific test being used.

Once tested, it’s technically the medical review officer (MRO) at the drug testing lab who ultimately determines whether a sample is positive or not. When a sample is flagged, they’ll contact you to ask if you have any prescriptions for legally prescribed cannabinoids (e.g. nabilone, dronabinol, etc). 

If you haven’t been prescribed one of these and you acknowledge past use, the MRO will then determine that the screen is positive. If there’s a dispute about positive results, the sample will be sent for GC/MS analysis. This is a much more sensitive test and usually performed at a lower cut-off.

This is why we highly recommend avoiding any THCa products if you have to take a drug test, as they can lead to positive test results.

thca test positive

How Long Does THCa Stay In Your System?

More research needs to be done on THCa but we can expect the amount of time THCa stays in your systems to be similar to THC-COOH. 

When looking at how THC-COOH is metabolized in the body, the length depends on a few factors. The biggest contributors are the total amount consumed and the frequency of consumption. Other factors include age, biological sex, water and body fat percentage and distribution, level of physical activity, and metabolism.  

There is limited research about THCa, but we can also look at research conducted on the inactive metabolite THC-COOH. Since we know that THCa converts to THC-COOH by the body we can assume that THCa will stay in our systems for the same amount of time.

A 2014 study examined the biological activity of certain metabolites of THC including THC-COOH in humans and animals. The authors acknowledged that current research is insufficient in determining the full extent of how THC-COOH is metabolized.

Contingent on the method on consumption and frequency of use, they found that THC-COOH remained detectable in blood at concentrations of 3-150 ng/ml. Blood levels peaked at one to three hours and stayed elevated for up to 20 hours when THC-COOH was smoked or taken orally. 

In terms of the total amount of time THCa stays in the body, the researchers discovered that it not only depended upon route of consumption but what part of the body was tested. 

Here’s what they found from the study:

  • THC-COOH remained detectable in the blood for about 10-20 hours
  • THC-COOH was present in saliva for up to 2 days
  • THC-COOH was present in urine for 3-4 days
  • THC-COOH levels were detectable in hair strands for up to 90 days

Wrapping Up: THCa Drug Testing

If you consume THCa and take a drug test, it’s highly likely THCa will show up. 

Even though it’s a non-psychoactive cannabinoid in its raw form, it is eventually converted into THC in the body. Then THC will convert into THC-COOH, the metabolite most drug tests are looking for. 

No matter the method of consumption, THCa is decarboxylated by our system and will inevitably become THC-COOH. That said, the cannabinoid will typically make a routine drug sample positive. 

Since research is limited, we can’t say with certainty how long THCa will remain in the body. If you’re scheduled for a drug test in the near future, however, we recommend you avoid THCa entirely.

Frequently Asked Questions (FAQ)

What is THCa?

Short for tetrahydrocannabinolic acid, THCa is the acidic form of THC. THC is minimally  present in the raw plant form and must be converted from THCa. 

According to research, THCA can “represent up to 90% of the total THC contained in the plant”. So THC becomes THCa after it is decarboxylated. 

THC and THCa are nearly identical except for THCa’s additional carboxyl acid chain. This one difference inhibits us from getting high. Once decarbed, that acid chain drops and we get to experience the euphoric effects THC is famous for. 

There are actually two types, or isomers, of THCa: THCa-a and THC-b. They both turn into THC when heated but little else is known beyond that. It’s THCa-a that’s considered the most prevalent form of THCa in raw flower. 

Is THCa Legal?

Yes, THCa is considered legal at the federal level. 

Thanks to the 2018 Farm Bill, hemp products that do not exceed 0.3% of Delta 9 THC on a dry weight basis are not a Schedule I Substance. THCa products that contain less than 0.3% THC are therefore permitted under the legislation. 

THCa is actually missing from the bill, so on this technicality it’s legal. This legal gray area is what allows manufacturers to create and sell products that contain THCa.

While THCa is federally unregulated, certain states have outlawed THCa products all together. If you’re interested in consuming THCa products, check with your state law to be sure of its legal status. 

Is There A Difference Between THCa and THC?

Yes. Although the two are very similar, they’re not exactly the same. They’re both cannabinoids and almost structurally identical. 

Contrary to popular belief, THC only exists in very tiny quantities in cannabis flower. It’s actually THCa that’s found abundantly in raw cannabis, which converts to THC after it’s heated via smoking, vaping or cooking. 

Because THCa is an inactive cannabinoid, consuming raw THCa won’t produce intoxicating effects. THCa does bind with certain receptors in our brain but not the ones that get you stoned. 

It’s only when THCa is heated that it loses that carboxyl group and becomes THC that the cannabinoid causes intoxication.