Saliva Drug Testing and THC detection

As many are aware accuracy of Saliva Drug Testing and the detection of THC is frequently questioned.
There is substantial research in the last 15 years that indicates that Saliva Drug Testing for THC is quite unstable, even with monumental advances in technology in recent years it still remains so.

I don't want to create a "how to buy good marijuana article" however some practical facts need to be covered as well as the technical information. 

Below is a typical product insert for a saliva test device showing the types of THC molecules tested. This tests detects both the Parent THC and the metabolite THC-COOH

 

Δ-9-tetrahydrocannabinol (THC) (Parent)	50 ng/mL
(-)-11-nor-Δ9-THC-9-COOH	12 ng/mL
11-Hydroxy-Δ9-THC	300 ng/mL
11-nor-Δ8-THC-9-COOH	12 ng/mL

The emphasis is on detection of the Parent Drug at 50ng as that is deposited in the mouth via when marijuana is smoked.
It is quite obvious that the amount of this molecule deposited in the mouth is entirely dependent on the 'quality' and 'quantity' of the substance consumed.
I am of the firm belief that the quality/potency is a major issue with detection in saliva.
For example if marijuana leaf is consumed in comparison to the head that has a high density of trichome, (sticky resin). With these two there is no comparison, if you ran a saliva test after someone smoked leaf it is possible to get a negative, if they smoked high density head laden with trichome it should be detected for Δ-9-tetrahydrocannabinol(THC) in saliva.

The issue = Potency - not all weed smoked has high potency, one could be 15% while another 65%, this will give very different results with a saliva test.

From a user perspective the weaker the Δ-9 THC content the more delayed the real high, because the high is dependent on the metabolite molecules, THC-COOH, this takes longer to enter the blood stream and is easily detected with a urine drug test.
As a matter of interest the highest potency molecule is 11-Hydroxy-Δ⁹-THC, detected in urine not saliva.

The end result for saliva testing is quite variable!
But it does remain a great deterrent for onsite testing

Here is the technical information for those who want to know the details: 

Rapid Saliva Drug Tests are a qualitative assays which indicates a "YES / NO" response to the presence or absence of drugs in the sample, giving a  "Presumptive Negative" or "Presumptive Positive/Non Negative" result.

 A saliva drug test for THC, whether in combination with other drugs to be assessed or standalone test, detects THC present in a sample in the form of Δ-9-tetrahydrocannabinol or Δ9-THC (parent drug), (-)-11-nor-Δ⁹-THC-9-COOH (metabolite), 11-Hydroxy-Δ⁹-THC (the main metabolite) or 11-nor-Δ⁸-THC-9-COOH (metabolite) Δ9-THC is the molecule or active ingredient of cannabis that can be found specifically in the mouth. The smoke of a marijuana contains a large amount of this molecule. The smoke will contaminate the oral cavity during smoking, and it leaves a trail for several hours. 

If the saliva sample has a THC level above the indicated cut-off of the device e.g. 50ng/ml, the test will indicate a presumptive positive, otherwise the test will be presumptive negative.

 Detection time of THC in saliva : whatever the test used, THC (the active ingredient in cannabis) can rarely be detected more than 4 to 12 hours in saliva. The detection time of many Saliva tests will therefore be 4 to 12 hours after the last smoke, although some say much longer, to do so would require an extremely low detection level for THC say <10ng/ml

 What is the difference between Δ9-THC and THC-COOH?

Δ9-THC, it is the correct abbreviated term used for the cannabis molecule in its raw or parent state.

THC-COOH (also called 11-nor-Δ9-THC-COOH or 11-nor-Δ⁸-THC-9-COOH) is the molecule of cannabis that has been converted by the body (the "metabolite" of cannabis).

The human body must indeed change the Δ9-THC in order to eliminate it. 11-Hydroxy-Δ⁹-THC which is rarely found in the mouth other than when cannabis is orally consumed, not smoked, crosses the blood/brain barrier very fast after processing by the liver, it subsequently produces 11-nor-9-carboxy-THC which has some analgesic and anti-inflammatory effect. The result of this transformation is essentially THC-COOH, found particularly in large quantities in the urine as it is excreted from the body.

 How to choose the right saliva test?

Because the predominant molecule present in the mouth after smoking is the Δ9-THC, with minor quantities of THC-COOH which has already been metabolised. Be aware that many saliva tests on the market are still designed to detect only THC-COOH at low cut-offs and a few will detect Δ9-THC at high quantities as well as THC-COOH. The tests that only tests THC-COOH are much less effective. The cut-offs are usually indicated as 12ng/ml for THC-COOH, this sometimes equates to 50ng/ml for Δ9-THC but not always, it depends on the strip manufacturer and reagents used in the test strip.  Tests that target the molecule of Δ9-THC can achieve better and more accurate results for marijuana use, and the lower the cut-off, the more effective the test will be.

Always review the product information or ask the supplier to determine if their saliva test targets Δ9-THC, or THC-COOH.

To choose a good saliva test for THC, it is important to understand that a test that targets the Δ9-THC at 25 ng/ml – 50ng/ml (most common) will be much more effective than a test that targets THC-COOH at 12 ng/ml . Although the second shows a detection limit lower than the first. The reason being there is a very small percentage of THC-COOH present and that is only after it has metabolised.

Many devices detect both however with an emphasis on THC-COOH therefore the test may not give a result for some time after consumption e.g. 2+ hrs after use, when there is a higher concentration of the THC-COOH.

Can a saliva test replace a urine test?

No, because these two types of tests do not answer to the same question.

Can a urine test check if a saliva test is working?

Only after a period of time, once the THC has fully metabolised and processed.

A urine test can be used to confirm the presence of THC in a candidate after a period of time has elapsed but not with a very short timeframe after use.

Saliva tests enables a screening on a very short detection period for THC. They are designed to tell if someone has recently used a THC (within a few hours), but not whether the person has a history of THC use over the last 10 - 30 days.

They answer the question: Has this person smoked marijuana during the last 4-8 hrs and used other tested substances in the last 24-48 hrs 

It must be noted that saliva testing for THC is notoriously complex and detection periods in any single individual cannot be easily determined.

In fact substantial research in the field indicated that it is impossible to define test times for THC. This is due to a multitude of variables both in the individual and in the quality of the THC consumed.

Individual characteristics such as age, sex, body weight, fat tissue (THC stores in fat), metabolism, and history of use all have a bearing on the possible results.

Of course, the quality of the marijuana is also critical in the process, low quality, low THC molecules will not produce the same results as high quality marijuana with high THC concentrations.

So the concept that I just smoked a joint or cone and then tested myself and it is negative has little bearing on the validation of the device.

In field testing with the best devices in the World had very low success with this method of test validation.

Note:

Any drug testing is not all about test results, testing, especially random testing is one of the best deterrents to working under the influence of drugs.

Because of the versatility and environmental requirements to use saliva tests, they are by far the most effective in deterring drug use.