My thought and experiences with drug testing in general:
I just graduated in December. Our school did not do drug testing prior to admission and I don't know if there was a policy in place that allowed them to do so for just cause. One of the clinical sites that our school used did require testing. We did not know until the first day of peds when the instructor said, "Raise your hand if you are going to X Hospital for clinical. Okay you need to do a drug test." (On our own dime, of course.) So there was no time to "modify" your behavior, if need be.
I find drug testing to be an intrusive violation, on principle alone. If I have given no just cause, don't make me prove my innocence. I really don't think that drug tests prove much. They just prove that either you can or can't modify your behavior for a specified amount of time (length of time depending on the drug and how it is metabolized and excreted). For those that test positive for Rx drugs, as long as they have documentation that they have a legal Rx than it's OK. Yet, most folks that are addicted to Rx painkillers began as legitimately prescribed patients (r/t chronic illness or injury) and they became addicted over time b/c their pain wasn't adequately managed or they didn't have the resources or time to use adjunctive therapy (PT, massage therapy, chiro...) leading to them obtaining illegally or Dr shopping. So they could have a legal prescription AND still be a drug abuser!
Consider the length of time certain drugs are present in urine: cocaine 12hours, meth 1-4d, codiene 2-3d, morphine 2-4d, heroin 3-4 and marijauna one month+! So yesderday you could have been snorting some coke and a few days ago shooting up heroin and you would probably come up negative. But LAST MONTH on a trip to Europe you could have smoked a joint and test positive. I am not advocating/condoning drug use at all but that doesn't make any sense when you consider that most research has proved that marijuana use poses little risk, is not addictive and has lots of medical uses. Due to the legth of time that it takes to be excreted (b/c stored in fat cells) it is the most common drug to come up in testing, yet (according to most) it is the most innocuous! I shudder to think of all of the drugs that were pumped into my daughter's body when she had cancer (not inc chemo) just to manage side effects- zofran, megace, reglan, phenergan, morphine, methadone, fentanyl... I have often thought if she ever relasped, if just making a batch of "special brownies" would be safer and possibly more effective.
I also had a clinical experience that reinforced my beliefs and made me sick. The hospital had mandatory drug testing on all pregnant women prior to delivery. This woman was a mess anyway- she had been raped and was agonizing over whether to keep the baby or not. The woman had not even seen her 2 day old baby yet and was emotionally unstable. THIS is when her drug results came in- she had tested positive to amphetamines and the social worker was on her way to see her and child protective services had been called. I did not believe the charge and kept questioning the woman, it just didn't make sense! Turned out that she had taken Claritin-D. I alerted the social worker and she investigated and came back and said that the dates didn't match when she said that she had taken the meds (should have cleared by then). UMMM, first how much research has been done specifically on pregnant women and drug clearance? I talked to the woman more and found out the she had brought with her on admission a 48h urine collection. That was how they had obtained the sample! This woman was tormented for NOTHING. She was treated like an unfit mother and a drug addict with no reasonable cause. This should not ever have to happen to anyone.