What Causes False Positive Urine Test Result For Cocaine?

Posted on Thu, 2 Feb 2017

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Thu, 2 Feb 2017 Answered on

Mon, 27 Feb 2017 Last reviewed on

Question : I recently had a urine drug test which came back that I had cocaine in my urine. I was told that my CDL would be suspended and my employer will not let me drive. I suspect I may have taken something over the counter that caused me to fail the test. What may have done that? I do not have any history of illegal drug use .....I do have severe allergies and do use supplements, essential oils and over the counter medications when I have health problems.

Answered by Dr. Bonnie Berger-Durnbaugh (55 minutes later)

Brief Answer:
Information

Detailed Answer:
Hello XXXXXXX

Antihistamines and decongestants are known to cause false positives on urine drug tests - not specifically for cocaine though. I can't find any data on essential oils and false positives. One substance that can give a false positive for cocaine are anything extracted from coca leaves. I am wondering, if the essential oils came from another country, if they may have had traces of coca leaf in them.

Avoid taking anything (including eating XXXXXXX seeds!) for 1 week prior to a drug test unless you were prescribed it from your doctor. If you do that, it will be documented in the doctor's records.

I recommend you request a follow up test. Not a repeat of the same standard test you just took, but gas chromatography plus mass spectrometry (GC-MS). This is the gold standard test for confirming a positive result on immunoassay. Because false positives do happen, about 5-10% of the time.

I hope this information helps.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar