How does a pre-employment drug test work?

Say a company did pre-employment drug testing. When would they typically do that, and would they give you a warning or a few days notice before doing it? Just wondering if they'd do it at an interview, or if its something more like, they test you once you are given the job or something?

How does a pre-employment drug test work?
when you interview they will give you a place and phone # to be tested. you call them and make an appt. the employer will probably give you a week to go get it done. thats how it worked for my husband anyway
Reply:When I first got a job at HSBC Bank, I was told at the interview that I would be requested to submit a sample for drug testing. The appointment had to be made within a week at the agency they used for testing. They can't drug test you at an interview - that would be considered random drug testing, and they can only do that if you are employed and it is a condition of your employment.
Reply:Drug testing is now required for Workmans Compensation or the insurance company for self-insured businesses. Where I live in Arkansas, you go through the interview and if they are going to offer you a job, you get the test the same or next day. I have been tested in the employers nurses office immediately. Hair tests can detect drug use for approximately 6 months previous.
Reply:usually they give you like a consent to sign at the interview saying that you are allowing them to drug test you, and then if youre hired you probably get your drug test during like orientation or something. i usually get the consent and sign it, but i havent gotten a job in a while :-(
Reply:Most companies will have you do a drug test when they are seriously considering hiring you, normally as the final step. There's usually no warning and some companies will go so far as a drug test using a hair sample(which will show if there has been drug use months back).
Reply:Jobs will never give you a drug test at the site of the interview. It will be after the interview, if you are hired on the spot they will give you a chain of custody form to take to the drug testing site, they will usually tell you where it is or give you a list of a few places to choose from in your area. They will also tell you how long you have to go take the test, many employers only give you 24 hours. But 24 is still enough time to go get a system cleaner and use it. Some jobs, however, will give you anywhere up to 10 days to go take your test, or won't even give you a deadline for it. You usually only have to take a drug test though unless you are definitely hired by the company.
Reply:Most often, you will go thru the interview. Then if they want to hire you, they would offer you a conditional job offer. The condition would be that you pass the drug screen. They will send you to a clinic to get tested.