Delta-9-THC: effects and differences between saliva, urine, and blood tests
Partager
What is delta-9-THC?
Delta-9-tetrahydrocannabinol, or delta-9-THC, is the main cannabinoid responsible for the psychotropic effects of cannabis. It notably affects attention, immediate memory, coordination, time perception, and reaction time.
Effects vary depending on the dose, product potency, mode of consumption, tolerance, health status, and combination with alcohol or other substances.
What does a THC saliva test detect?
A saliva test generally detects delta-9-THC present in saliva. It is mainly used to identify recent exposure, but the detection window varies greatly depending on the mode of consumption and the person's habits.
A rapid test provides a presumptive result. In the French roadside procedure, saliva THC screening must meet a minimum detection threshold of 15 ng/mL. After a positive screening, confirmation analysis in a laboratory uses a chromatographic method coupled with mass spectrometry, with a minimum analytical threshold of 1 ng/mL of saliva.
What does a urine test detect?
For cannabis, urine tests most often detect THC-COOH, the main metabolite eliminated in urine. It can remain detectable longer than THC in saliva.
A positive urine result therefore generally indicates prior use, without allowing precise determination of the time of use or the person's state at the time of sampling.
What can a blood analysis provide?
Blood allows quantitative analysis of THC and other substances in a laboratory. It is used in certain medico-legal or medical contexts, especially when a counter-expertise is requested according to the applicable procedure.
Blood concentration decreases rapidly after consumption and its relationship with effects is complex. There is no universal correspondence allowing precise deduction of fitness to drive from a single figure.
How long does THC remain detectable?
No fixed duration can be guaranteed. The window depends on frequency of use, dose, product potency, mode of consumption, metabolism, and test threshold.
- Saliva mainly informs about recent exposure;
- Urine can remain positive longer, especially in case of regular use;
- Blood provides an analytical measurement in a specific context, but its interpretation requires expertise.
How to interpret a rapid test result?
A positive result should be considered presumptive and may require laboratory confirmation. A negative result only means that the target was not detected above the test threshold at the time of sampling.
Discover Drugdiag® saliva tests
