Drug screening refers to a process where a person's blood, urine, or other samples are tested to check for the presence of illegal drugs or medications. It is done to determine if someone has been using drugs recently. Full definition
Here, we look at some of the fundamental research that enables it to supply liver and pancreatic cells for drug screening. (cam.ac.uk)
If that means that I have to have urine drug screens, so be it. (health.com)
I've taken drug screens in the past and none of the never took more than 3 hours, some I was given the results minutes after the screen. (campus-to-career.com)