According to Thomas Dobie, who used to work in a drug testing lab, you’d have to be an idiot to fail a drug test for cocaine. "Cocaine, honestly, if you do it infrequently -- maybe on a Friday night when you go out with your friends -- it's only in your system for 24 hours," he says. A chronic abuser would have the drug in his system a little longer than that, Dobie estimates, perhaps 48 to 72 hours. (Most available resources support his claims, although a few suggest that a very heavy user could have evidence of the drug in his or her system for 10 to 22 days.)

There are a lot of idiots out there, though. Some of them, in fact, are trying to get into the drug-testing business. Dobie worked for Kroll Laboratory Specialists, a Gretna, La., drug-testing lab. He recalls a time when a prospective co-worker failed a pre-employment drug test. "We had someone come in and interview with us and they were a great candidate -- great GPA, came from a great university,and they failed for cocaine." Dobie figures the candidate had probably done cocaine very shortly before the interview. "If you're going to get a job at a drug-testing lab, and you do cocaine the night before, you're the biggest idiot I've ever met," Dobie says.

That goes for the rest of you, too. The best way to beat a drug test is simple, cheap and easy: Don't do drugs in the weeks leading up to the test. And there's a pretty good chance you're eventually going to have to take a drug test. According to a 2004 American Management Association (AMA) study, 61.8% of companies surveyed said they test employees for illegal substances. Some might say that's for good reason, as three out of every four current illicit drug users in the United States are employed, and companies are losing roughly $81 billion a year in lost productivity due to drug use, according to the Department of Labor.

While random tests are common at some employers, particularly in safety-sensitive industries like transportation, you'll most likely get sufficient advanced warning about a drug test. According to the AMA study, 52.5% of workplace drug tests are used to make decisions about hiring an applicant, and 8.5% are used in decisions to assign or reassign employees.

Marijuana will stay in your system the longest and will require the longest period of detoxification. Depending on the source of your information (and there are many available online), marijuana can be detected in your system for a few weeks and up to a couple of months (12 weeks was the most generous number we found) after last use. As with most drugs, it will remain in your system longer with habitual or chronic use. Dobie estimates that a typical, frequent marijuana user will have evidence of it in his or her system for about three weeks. So, erring on the extreme side of caution, it's probably best to refrain from smoking pot three months prior to testing. Also, it'd be a good idea to remove the picture of you doing a bong hit from your FB profile.

If you've decided to smoke, snort or inject yourself silly regardless of impending tests, there are other ways to pass, and those fall into two main categories. First, you could alter your own sample by flushing your system of the evidence of drug use or by adding something to your urine in the time after you pee into a cup, but before you hand it in.

Second, you can use urine that isn't your own. During his time at Kroll, Dobie saw his fair share of altered samples. The laboratory would catch many of them. So, consider this a lesson: Don't just add something to your urine, especially if that something is an everyday household product. Regardless of what that dude you smoked with last Saturday night told you, more times than not, you will get caught. In fact, a sample with additives will often be apparent to a tester's naked eye. "I don't know what the hell they put in it, but they've given us purple and green pee. I mean, it's ridiculous. People will add anything, they'll try vinegar. They'll add anything under the sun," Dobie says.

Some people believe that soaps, particularly dishwasher detergent, will make a sample test negative. In reality, it may doom you from the start. Even if something like detergent doesn't change the color of your sample (which would almost certainly raise a red flag), it may cause it to bubble when transported or transferred to a test tube. And obviously, a scientist will be suspicious of bubbling piss. Any such irregularities in a sample would require additional tests. "We had a special test to see if there were any sufectants (such as dish detergent) in a sample," Dobie says.

Oh, and bleach won't help either. It's likely that scientists will know you've added it, and besides, Dobie says you'd likely still test positive for the original drug use. "It's not going to do anything. You're still going to fail." As for that dude you smoked with on Saturday, his story isn't necessarily bogus. There is some chance that an additive will work. Dobie recalls a sample that testers believed to be positive, but an unknown substance prevented a positive confirmation. "We knew damn right they were positive, but we couldn't get it within the right limits to actually legally confirm it," Dobie says.

Instead of trying to mask a urine sample that will likely test positive, you could try flushing your system of the toxins that cause a sample to be positive in the first place. In other words, drink lots of water before your test, and urinate frequently. Many drug-test veterans we spoke to suggested that this was the best way to pass a test. One employee of a major Hartford insurance agency suggested a special drink, available at stores like GNC. It's one of many products that promise to help the "flushing" process along. A visit to a GNC and a Vitamin World at the Westfield Shoppingtown Mall in Enfield found such a product, along with pills and special shampoos (for hair tests). It's best to find the products yourself, as store clerks would not help us when we specifically asked for drug-testing products. You'll know when you've found the right stuff.

A college student from Westchester County, NY, swears by some pills he bought at Mrs. Greens Natural Market, which he took along with copious amounts of water and topped off with one glass of milk. "I smoked marijuana basically every day until five days prior to the test and then I took the pills the day of the test," the 20-year-old, who was looking to work last summer as a wine clerk, says. "After a few weeks went by, I found out that I got the job." Dobie isn't sure which products work and which don't, but he does say it is possible to flush your system enough to avoid failing a test. "If you do habitually smoke marijuana, and you're told you're getting tested in two days, then hell, in my situation, I'd try everything there is out there and flush my system as much as I possibly could," he says. However, whether you just drank lots of water or juice, or supplemented that process with something from your friendly neighborhood vitamin store, it will likely be apparent to drug testers. Your urine will be clear--and that's a sign that you've flushed your system. Such a sample may also be flagged for additional tests to make sure it isn't just water.

So, while flushing your system may save you from a failed test, it doesn't necessarily mean you'll pass, either. Regardless, you'll likely have more time to detoxify before a retest, although that retest may be stricter and more closely monitored. "It's a little suspicious, but chances are they can't fire you unless you really test positive," Dobie says. For the really brave (or really desperate), you can also try submitting a sample of someone else's (presumably drug-free) urine. If you're able to pull it off, it's the most dependable way to pass the test.

After all, a scientist like Dobie just sees a sample in a test tube. There's no test to match the piss to the pisser. "If you can just tape some kind of test tube with a friend's urine in it to your thigh so it's about as warm as your natural body temp, then you're going to pass," Dobie says. However, it's not the easiest thing to pull off. Some tests are preceded by a pat-down and others are literally observed (read: someone watches you pee) by the test administrator. Many samples are immediately checked for temperature. There are products available to deceive monitors in the case of an observed test (read: a fake penis that dispenses a clean urine sample) and they're available online.

Last May, Onterrio Smith of the NFL's Minnesota Vikings was briefly detained by airport security when one such device known as "The Original Whizzinator" was found in a bag he was carrying. If you're not confident of your friend's ability to give you a clean urine sample, Dobie says that's not a problem, either. You can just make your own synthetic urine. He suggests that if you knew the proper amounts, maybe by consulting a chemist, you could combine water, yellow food dye and creatinine (a breakdown product found in all mammals' urine) to make a passable urine sample.

We say: Good luck finding creatinine. By doing so, you'd create a substance similar to Kroll's double-blind samples, which are synthetically made in the lab to be used as a control in the testing process. So long as the sample contains the proper amount of creatinine, it won't "blank out" during the test. "As long as you have creatinine and it's yellow, you're -- excuse the pun -- golden," Dobie says. In the end, if we had to take a drug test (which we don't) and were habitual drug abusers (which we swear we're not), we'd stop using for the time being and try our best to flush our systems. It's a fairly reliable way to pass a test. Even better, it's not cheating. You're not physically altering your urine with an additive, and you're not passing in a sample you made with a chemistry set or that you got from a drug-free friend. You're just speeding up a natural process.

Our Drug-Testing Friend
For a time, Dobie was a negative certifying scientist. He’d confirm that someone passed the test by looking over the data of a given sample and confirming that it tested below minimum values for whichever drugs were being tested for. Later, he began work as a positive certifying scientist. He would look at samples that initially showed evidence of drug use, add the pertinent chemicals and run it through a GCMS, or Gas Chromatography Mass Spectrometer. By doing so, he could confirm what a preliminary test had already shown—that a given urine sample had tested positive for a specific type of drug. “It was my job to make sure that these people were confirming positive. At that point, I’m basically saying this person is losing their job, or not getting hired, or just failed their parole, and so on and so forth,” Dobie says. Dobie left Kroll to pursue a dental career. He’s currently enrolled as a graduate student at Tulane University.

Is There a Drug Test In Your Future?
Got an addiction? Need to know how long to endure drug withdrawal to ensure a passing urine drug test? There are plenty of charts available on the Internet that tell how long a certain drug can be detected in your system, but they’re all slightly different. We’ve stolen a little bit from each of them here, but be warned: the time will be much longer for a hair test.

Marijuana:
2 days to 11 weeks

Cocaine:
1 to 4 days Heroin: 2 to 4 days

Alcohol:
6 to 24 hours (so just don’t be hammered while taking the test)

PCP:
3 days to 2 weeks

Conclusion:
Any casual drug user should be in the clear after 11 weeks.