How Long Does Cocaine Show Up in a Drug Test?

You’re out bar-hopping with an old friend from college when he takes out a familiar little baggie of white powder. You’re hesitant, but when he starts cutting the coke into lines with a credit card, all cinematic-like, you think, “What the hell?” You lean down, put a finger on one nostril and snort. Three hours later, you’re still at the bar rapid-fire rattling off all your ideas on how Battlestar Galactica should have ended.

Later that week, your boss hands you a plastic cup with a testing lab’s logo on it and you remember that you’re not Stooges-era Iggy Pop, but a working grunt subject to drug testing. As you head to the bathroom, you wonder just how long cocaine stays in your body.

The good news is that the window for cocaine detection in a urinalysis or saliva test is so short that you pretty much have to be coming down from a high while pissing to be detected. This is particularly true if you’re an infrequent user: A one-off sniff of a small amount of cocaine might be undetectable within hours. “It could only take 12 hours for anything less than half a gram,” says Lisa Tomsak, medical director of Royal Life Centers, a rehab business near Miami.

Unlike cannabis, cocaine is not fat-soluble. This means it doesn’t stick around in the body’s cells after intake. Tests that utilize urine or saliva are actually searching for cocaine metabolites, small molecules that are byproducts of the body processing the drug—and these flush out of the system pretty quickly. While cannabis is detectable for three or four days since last use in occasional smokers and about three to six weeks in habitual users, signs of cocaine use are usually gone within the span of a weekend.

“For most drug users, it takes one to two days [to be untraceable],” says Barry Sample, the director of science and technology at Quest Diagnostics. (Yes, the science guy at one of America’s largest diagnostic testing companies is actually named “Dr. Sample.”) The method of delivery—intravenously, nasally, or through smoking crack—is mostly irrelevant. The quicker the drug hits the bloodstream, the quicker it leaves the body. Intravenous use is instant, while snorting and smoking create a slower pathway, but the difference isn’t enough to effect the window of detection much. Even for heavy users, these metabolites don’t accumulate or stay around for long.

“No two people we test are identical,” Tomsak says, “but it should be out of your system in seven days. That’s supported in the literature.” If there are still metabolites in your system after that, there’s probably something wrong with your kidneys, she adds. Studies of cocaine detection have varied in their results and methodology, but usually they measure the time it takes for metabolites to leave the body in hours, not days. But there is another method of testing that can detect blow after months of living clean and sober, and employers who really want to avoid hiring coke users are utilizing it.

Follicle testing is not a common way for employers to administer random tests or post-incident tests to those who are already on the payroll, Sample says, but it is a way some businesses are screening job applications because this method can trace drug usage months after the last high. It’s practiced in industries with heightened safety concerns, like oil and gas and transportation.

As the drug makes its way through the body, traces of cocaine get mixed up in the process of follicular morphogenesis, the growing of hair (as do opioids meth, ecstasy, marijuana and a host of other drugs). “It’s circulating through the bloodstream and the hair follicle is exposed to blood in the shaft,” Sample says. “Cocaine can be growing in your hair.”

There is no expiration point for cocaine compounds in your hair. They just stay there until you cut it. It’s more likely to test positive the more cocaine you do. If you have done coke excessively or recently, the best course of action, Sample says, is to cut your hair. The most recently generated bits of hair strands are closest to the roots, so chop off the bits that may have been in production when you last used and you’re safer.

It may sound weird and even creep-ish for an HR manager to ask for a bit of your hair. Expect more precise forms of drug testing in the future, says Laz Versalles, director of development for Accesa Labs, a Los Angeles-based company. “There is a new arm of drug testing that’s looking for new levels of scrutiny,” Versalles says. That’s because of the changing perception of drug use in the US. Recreational cannabis use is legal in nine states and socially acceptable in almost all. Some employers are declining to test for it.

Opioids are an epidemic, but painkillers are often prescribed as part of a medical regimen, and employers aren’t sure if it’s worth the legal hassle and complication to consider them as a barrier to employment. Many drug tests in the future, likewise, may be strictly for illegally, socially stigmatized drugs like meth, PCP, and cocaine. A hair test presents more of a challenge and if you have to give over some follicles to get a job, you better grab the clippers and hope a close crop or a pixie cut works for you.