Blood tests utilized in cases of driving under the influence (DUI) of marijuana can identify traces of the drug in the bloodstream more than 12 hours after consumption. In individuals who use marijuana regularly, it can be detected in the blood for up to a week.
This information can be crucial in legal proceedings related to drugged driving, as the presence of marijuana in the blood can be used as evidence in a DUI case, regardless of whether or not the individual was actually impaired by marijuana at the time of arrest.
Can blood tests detect my THC?
Yes, blood tests are capable of detecting tetrahydrocannabinol (THC), which is the primary psychoactive component found in marijuana.
These tests analyze cannabinoids or the metabolites of cannabinoids present in a blood sample. Marijuana contains over 100 different cannabinoids, and when the body processes marijuana, it produces cannabinoid metabolites.
Most commonly, blood tests focus on measuring the levels of delta-9-THC or its metabolites. Occasionally, these tests may also measure levels of cannabidiol (CBD) in the blood sample.
Are Blood tests reliable for marijuana DUI cases?
Blood tests are not entirely reliable for establishing impairment in marijuana DUI cases for several reasons:
- Persistence of THC: THC can remain detectable in the bloodstream long after the psychoactive effects have dissipated.
- Lack of Standardized Legal Limits: Most states do not have a universally accepted legal threshold for THC concentration in the blood.
- Variability in Impairment: Different individuals may experience impairment at varying levels of THC.
- Influence of Usage Frequency: Regular users may retain THC in their bloodstreams for extended periods.
- Body Fat Influence: Since THC is fat-soluble, individuals with higher body fat percentages may retain THC for longer durations.
- Method of Consumption: The mode of marijuana ingestion can affect how long THC remains in the bloodstream.
Can I other tests detect cannabis?
Several tests are available to detect THC, the psychoactive compound in cannabis, including:
- Urine Tests: These can detect marijuana use in casual users up to 3 days after ingestion. For heavy users, detectable levels can persist in their urine for 10 days or more.
- Saliva Tests: THC can be detected in oral fluids. Saliva tests can yield positive results for up to 29 days following ingestion, depending on the sensitivity of the test and the frequency of use.
- Hair Samples: While capable of detecting marijuana, hair testing is not practical for DUI cases. It takes about a week for THC, CBD, or cannabinol (CBN) to be detectable in hair follicles, and these substances can remain in hair for several months.
Despite these options, there are challenges similar to those with blood testing, primarily related to the timing of detection rather than current impairment.
Breath Tests: Currently, there are no commercially available reliable breath tests for marijuana, but research is ongoing to develop such a test that can detect marijuana in breath shortly after use.
What other evidence can be used in a drugged driving case?
In DUI-drugs cases, especially those involving marijuana, law enforcement officers rely on various types of evidence in addition to blood tests. Here are some common forms of evidence used in marijuana DUI cases:
- Officer’s Testimony: An officer may testify about smelling marijuana in the vehicle, which can suggest recent use by the driver.
- Marijuana Presence: Finding marijuana in the car can lead not only to DUI charges but also to drug possession charges, particularly in states where marijuana is not legalized.
- Drug Paraphernalia: The discovery of items like bongs, rolling papers, or other drug use instruments in the vehicle can result in charges of possession of drug paraphernalia.
- Observations of Impairment: If the officer notices signs of impairment such as bloodshot eyes, slow reaction times, or unusual calmness, and if no alcohol is detected in the person’s system, these observations can support a DUI charge.
In cases where no blood test is available, the entire case may hinge on this type of evidence. Officers often provide testimony describing behavior typically associated with drug use, including:
- Anxiety or unnatural calmness,
- Bloodshot or red eyes,
- Slowed reaction times,
- Inappropriate laughter,
- Restlessness,
- Lack of attention or frequent distraction.
This officer testimony, especially in the absence of video evidence from body cameras or dash cams, can be challenging to contest.
What is the legal limit for marijuana?
There is no universally accepted legal limit for THC or marijuana, which distinguishes drugged driving cases from those involving alcohol. Alcohol-related DUI laws establish a clear legal limit; for example, the general blood alcohol content (BAC) limit is 0.08 percent. However, there are exceptions based on specific demographics and professions:
- For drivers under the age of 21, some states set the limit as low as 0.02 percent, and in others, it’s zero.
- Commercial drivers typically face a stricter limit of 0.04 percent.
- Utah has set its limit for regular drivers at 0.05 percent.
Exceeding these BAC limits typically results in a presumption of impairment, making it difficult to contest charges based on chemical BAC tests.
Contrastingly, only a few states have set a legal THC limit for driving, often at 5 nanograms per milliliter (ng/ml) of blood. The application of this limit varies:
- In Washington state, this limit is treated similarly to alcohol, where exceeding it implies per se impairment.
- Colorado uses a more lenient approach, where exceeding the THC limit allows for a permissible inference of impairment rather than an outright determination.
Given the complexities and variability in how THC limits are applied, defending against a DUI charge involving marijuana often requires skilled legal representation to navigate the nuances and protect the accused’s rights.
For how long does marijuana impair driving?
The duration of impairment from marijuana can vary significantly depending on individual sensitivity to THC and the method of consumption. While effects are subjective and can differ widely, a study indicated that most people no longer felt impaired approximately three hours after smoking marijuana.
In California, it is illegal to operate a vehicle while under the influence of any drug, including marijuana. Unlike alcohol-related DUI regulations, California does not have a specific legal THC limit that establishes impairment. Instead, to secure a conviction for DUI under the influence of marijuana, prosecutors must demonstrate:
- Vehicle Operation: The defendant was driving a vehicle.
- Impairment: While driving, the defendant was under the influence of marijuana, affecting their mental or physical abilities to a degree that they could not drive safely.
The assessment of impairment is comprehensive, requiring more than just poor driving patterns. It involves considering all relevant circumstances surrounding the incident.
Given the complex nature of such cases and the absence of a definitive THC impairment threshold, having a competent DUI attorney is crucial. An experienced attorney can challenge the prosecution’s evidence, potentially arguing points such as the lack of probable cause for the traffic stop, to mount an effective defense.
