Secondhand Dope Smoke: False Positive or Fallacy?

Nov. 19, 2007— -- Amy Winehouse's tour manger abruptly quit last week, complaining that the sultry singer smoked so much heroin on her tour bus that he tested positive for the drug just by inhaling her secondhand dope smoke.

Experts were baffled as to why Thom Stone had himself tested but also expressed skepticism that heroin could have shown up in his system simply because he in close proximity to the toking rock star.

As first reported by British tabloid The Sun, Stone reportedly gave notice to the English singer one day after she bombed ontage during a Birmingham, England, concert in which she cursed at fans and stumbled across the stage.

Stone reportedly told Winehouse, 24, known as much for her sexy sounds as for her reputed drug and alcohol abuse, that doctors had discovered the narcotic in his blood.

The dangers of secondhand cigarette smoke are well known, but can passively inhaling other drugs such as marijuana or heroin yield a positive result on a drug test?

Probably not, doctors told ABC NEWS.com.

"It's a long shot," said Dr. Daniel Lieberman, a psychiatrist and drug-testing expert at George Washington University Hospital.

"It is hard to imagine what his motivation for getting this test would have been in the first place, but it is unlikely that simply being in close proximity would have yielded a positive result," he said.

In the U.S., the standard for a positive test result is 2,000 nanograms of the drug per milliliter. "A person would need to sit in a cloud of smoke so dense their eyes would sting before they tested positive," he said.

Previously, the standard was 300 nanograms per milliliter, but the test would sometimes yield false positives if the subject had recently eaten poppy seeds. Yes, the myth was true.

"The cutoff had to be changed because of false positives resulting from poppy seeds," said Laura Shelton, executive director of the Drug and Alcohol Testing Industry Association. "The number of poppy seed bagels you'd have to eat to get a positive result now is astonishing."

Moreover, heroin metabolizes in the body within a few hours, making it additionally difficult to find in drug tests, Lieberman said.

"Athletes who test positive for marijuana also often blame secondhand smoke," he said. "But that would also require sitting in an incredibly dense cloud of smoke. All one has to do if they're worried is sit near an opened window. It is difficult to understand or speculate as to why [Stone] would remain in an environment so toxic he would test positive, but was never so worried that he would just get up and leave."