Keeping marijuana a controlled substance means having the ability to enforce it. Possession of the drug is still a federal crime. The ability to prove beyond a reasonable doubt that the person is in possession of marijuana is paramount in making sure that the people that are prosecuted are guilty. We are innocent until proven guilty.
In the past, the enforcement of anti-cannabis laws was more simple. The plant has a distinctive look and odor that can immediately identify the plant to police. Just the smell of cannabis was probable cause to pull someone over or have them searched.
Hemp has unwittingly changed things. The plant has now been made legal for cultivation as an agricultural product, and legal for consumers to purchase and use. The two plants are both cannabis, and while their appearance can change depending on the variety, they remain very similar.
The introduction of smokable hemp that looks, smells, and tastes just like marijuana is understandable confusing to law enforcement. The field tests they used to perform are no longer able to identify if they are holding a legal product of the illegal psychoactive drug.
The burden of proof has fallen even heavier onto the crime lab to determine this. So the question comes to mind, how do we test to identify marijuana?
How is marijuana currently tested for in the lab?
Today almost all labs use what is called the Thorton-Nakamura Protocol to identify marijuana. It is a series of three tests that are supposed to identify the presence of marijuana. The three tests are microscopic morphological examination, the Duquenois-Levine test, and Thin Layer Chromatography.
All three tests are supposed to identify marijuana, and they do, but there is very little evidence that marijuana is the only thing they identify. Each test is weak to false positives and cross-reactivity. Each test has not been validated to prove the presence of THC in a sample definitively.
All three tests are verifiable, but labs neglect to collect that evidence. There is never a second person that double-checks the test for accuracy. The people that are performing these tests are not trained scientists, but lab techs who have been trained in the mechanics of each procedure, but are otherwise unable to elaborate on what each test is trying to do.
The justice system believes that using all three tests done together will produce a valid result. Again there is no meaningful evidence that these tests can validate a measure for THC. There isn’t any research that shows that THC is detected and nothing else. The door is open at every stage for false positives and cross-reactivity.
There are also some presumptions that each technician is making. They are presuming that the samples are homogeneous when there is no evidence that they are. Three samples are taken, and each is independently tested.
All this and now we need more.
At this point, it would be valid to question how we test marijuana currently. All this and there’s more. It is debatable whether or not these tests can determine if a plant contains THC in the first place.
The problem is compounded with hemp. We know that hemp contains THC, even if just a tiny amount. Any test that detects THC will read positive for both marijuana and hemp. The tests that most crime labs have in place are now obsolete. There are tests to show how much THC is in a sample plant, but the equipment costs hundreds of thousands of dollars. To help law enforcement to do their job, they need access to labs that can do the tests.
Plans are underway to fund new equipment or fund contracts to test samples cheaper. Hopefully, this problem will be solved in a year or so. For now legalizing hemp has the unintended side effect of giving law enforcement a headache.