Drug tests seem backward.


Why are breathalyzers used to test something you drink and a urinalysis used to test something you inhale?

In: Biology

Alcohol goes into the blood. The blood goes into the lungs. The alcohol “evaporates” into the air in the lungs that you then breath out. We can measure this and using a ratio we can determine how drunk you are.

THC is inhaled into the lungs. From the lungs it goes to your blood. The metabolites (left overs) of THC are stored in your fat, seep into your blood over time and comes out through your urine as your body “cleans” your blood. We can detect these THC leftovers in your urine.

This is as ELI5 as one can get without going into technicalities.