Only a small amount is used for any given test so a sample could be tested many times.
Yes.
This is to preserve the urine sample until its tested.
So that the sample can be run twice. It's a standard in forensic science to that verifies the results of testing.
Both will show in a urine sample if tests are done to look for those drugs.
Urine, blood and hair are commonly tested for drugs.
Testing for alcohol can be performed with an alcohol breath machine, with a sample of blood drawn, with a sample of urine, with a sample of mouth fluid, or with a sample of sweat.
I don't know the limits but they test urine for marijuana
A urine sample usually lasts up to 7 days if frozen.
there are many myths. somethings work for some people but not others. you should have quit if you knew you were getting tested.
Four things: doing illegal drugs; taking legal drugs that cross-react with illegal drug screens; adulterating your sample through dilution, taking a masking agent that can be tested for or dumping something in the sample; or having a disease that will trigger a urine drug screen.
Athletic Drug TestingThe most common method of testing is chemical analysis using a urine sample. An athlete at the Olympics is required to give two urine samples (commonly refered to in the media as the A and B samples - which are kept in separate places). The A sample is tested chemically for substances on the banned substance list. If a substance is detected in the A sample the B sample is then tested. If both samples are positive for a banned substance then the athlete is asked to explain the findings at a hearing.
Why do you wanna know? You shouldn't be doing drugs!