frank frankie asked
I am on a list for a liver transplant. I may not have alcohol or opiates. I am on a new antibiotic called levofloxacin. My recent blood work turned up trace amounts of both alcohol and opiates. could levofloxacin be creating a false positive?
At a glance
- Levaquin (levofloxacin), and quinolone antibiotics in general, have extensive documented evidence that they can cause false-positive results for opiates/opioids on urine drug screenings.
Answer
Levaquin (levofloxacin) is classified as a 'quinolone' antibiotic.
Multiple studies have shown that quinolone antibiotics, like Levaquin, can cause false positives on urine drug screenings for opioids and opiates.[1]
So, in your situation, having tested positive for an opioid despite not taking one, Levaquin could be the potential culprit that caused this reading.
If you have the opportunity, try to request to have a confirmatory test done. Urine drug tests are notorious for false-positive results. They should ideally only be used as an initial screening according to most studies on the matter because of this.[2]
Why Do False-Positives Happen?
False-positive results on urine drug screenings are relatively common unfortunately, simply based on how these tests work.
They utilize antibodies to bind and react to a particular drug substance. False-positive results occur when an antibody binds to the wrong drug substance, which typically occurs with drugs that have a similar molecular structure to the compound being tested for (but this isn't always the case).[3]
How often false-positives occur isn't specifically known, but since they are well documented, it is important to be aware of the possibility of them occurring.
Levaquin False-Positives
Quinolone antibiotics have been studied extensively for their role in potentially causing a false-positive result on urine drug tests. All of the following quinolones have published studies implicating them as being potentially responsible for erroneous test results:[4]
- Levaquin (levofloxacin)
- Cipro (ciprofloxacin)
- Ofloxacin
- Gatifloxacin
- Pefloxacin
One study, based on their results, named Levaquin (levofloxacin) as one of the most likely quinolones to cause false-positive results for opiates:[5]
