Dear Alice,

My dad requires me to take weekly drug tests since he found out that I was smoking marijuana. My first test came back positive for marijuana and cocaine. I was not surprised about the marijuana because I had only been clean for five weeks, but I have never done cocaine. Is there anything that could have triggered a positive result? Could opium or mushrooms or any other drug possibly trigger this positive result?

Dear Reader,

If done correctly, drug testing for cocaine is pretty accurate. Most drug tests that check for cocaine look for benzoylecgonine, a product of the body's metabolism of the drug. Other illegal drugs, including opium and psilocybin, do not produce this byproduct and so can't cause a false positive for cocaine. Rarely, marijuana may be laced with other substances; accidentally using cocaine in this way could make someone test positive. However, benzoylecgonine can only be detected in urine for around three days after using cocaine. Your five weeks clean at the time of the test probably means that cocaine-laced marijuana isn't the culprit in your case.

That said, some medications and medical conditions can sometimes trigger a false positive for cocaine. These include:

  • Amoxicillin
  • Topical anesthetics derived from cocaine (does not include lidocaine or novocaine)
  • Liver disease
  • Kidney disease
  • Diabetes

One last possibility for a false positive is ingesting coca, the plant from which cocaine is derived. Coca leaves, particularly when brewed as a tea, are popular in a handful of countries but banned in the United States.

Since it sounds like you took an at-home drug test, there could be an increased likelihood of user error or false positives. A more specific secondary test, preferably by a professional, would need to be performed in order to figure out for sure whether it was cocaine, a different substance, or an error with the first test that caused the positive.

The U.S. Department of Health and Human Services and the Substance Abuse and Mental Health Services Administration (SAMHSA) recommend asking your health care provider whether your prescriptions might interfere with a drug test. Since you aren't using cocaine or other illegal drugs, this information should help you and your father understand the significance of the positive result.


Submit a new response

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Vertical Tabs