LOL, why would you bring a bag of weed to work, at a nursing facility? Honestly.
We recently had a bunch of random drug tests...because one of our kitchen workers was acting really hateful and out of character for him, and when his boss asked him what was wrong, he replied "Sorry, I took a bunch of my mom's oxycontin this morning and I just feel out of it."
But yeah, that was the first time my facility had them in the time I've been there. I'm told that in the past, they would just occasionally spring them on a handful of people. Everyplace I've been has just done either a urine screen, a saliva test, or a hair test. One should be sufficient unless you have suspect results.