Avoiding False Positives - What Else Can Affect a Test

Whether it’s for work, sports, or personal reasons, drug testing can be stressful — especially when results don’t tell the whole story. False positives happen more often than most people realize, and they can occur for many different substances, not just cannabis.

At The Next Level, we focus on education, not judgement. Understanding what causes false readings and how to prepare safely can make the testing process a lot less intimidating.

How Substance Testing Works

Most workplace and at-home tests use immunoassay technology — a quick screening method designed to detect metabolites, or the chemical traces your body leaves behind after processing a substance. These tests don’t measure impairment or recent use; they simply flag the presence of certain compounds above a threshold.

While convenient and inexpensive, these screens aren’t perfect. They can cross-react with other compounds that look similar at the molecular level, resulting in a false positive.

Common Causes of False Positives

False positives can occur for several reasons — and across multiple panels:

• • Medications – Pain relievers such as ibuprofen, naproxen, or certain antidepressants and decongestants can mimic results for THC, amphetamines, or barbiturates.
    
  • Supplements – Vitamins containing riboflavin (especially hemp-derived) and some herbal blends may trigger positive results.
    
  • Foods – Poppy seeds can register as opiates; hemp foods or herbal teas may cross-react on cannabis panels.
    
  • Nicotine substitutes – Some nicotine pouches or vapes contain trace alkaloids that resemble amphetamine metabolites.
    
  • Health factors – Dehydration, high acidity, or an imbalanced pH can alter a urine sample’s chemistry.
    
  • Expired or mishandled tests – Improper storage or old test kits can give unreliable readings.
    
  • Sample handling – Contamination or cross-transfer errors can happen even in controlled environments.
    

How to Reduce the Risk

There’s no way to guarantee a perfect result, but a few careful habits can reduce the chance of false readings:

• • Hydrate steadily, not excessively. Consistent water intake helps balance your sample.
    
  • Avoid unnecessary medications or supplements 48 hours before testing (unless prescribed).
    
  • Stick to light, balanced meals and avoid overly fatty foods that slow metabolism.
    
  • Rest well — stress, fatigue, and dehydration all affect pH and metabolism.
    
  • Check expiry dates on all tests and store them in a cool, dry place.
    

Testing at Home for Peace of Mind

At-home tests are a smart way to check your status before official screening.

U-Test THC Collection
Available in multiple sensitivity levels — 15 ng/mL (ultra-sensitive), 50 ng/mL (standard), and 15–300 ng/mL (multi-level). These single-step tests provide quick results within minutes, letting you track your progress or verify a clean result confidently.

U-Test Multi-Panel Kits
Offered in 3, 5, and 12-panel options, these tests detect a range of common substances such as THC, amphetamines, opiates, and more. Each provides fast, private results with clear instructions and built-in interpretation guides.

Testing yourself first gives peace of mind — and helps identify any unexpected cross-reactions before the stakes are high.

Fairness, Reality, and Harm Reduction

Cannabis may be legal in Canada, but drug testing hasn’t caught up to common sense. Many workplaces still enforce outdated zero-tolerance policies, even though urine tests can’t measure impairment — only residual presence.

That disconnect leaves a lot of good people in tough positions. At The Next Level, we can’t change the system, but we can help you navigate it safely and confidently. Our focus is education, transparency, and judgement-free support — no gimmicks, no guarantees, just honest information.

Continue the Series

Missed the last post?
Learn how synthetic urine and fake pee work in Synthetic Urine — What It Is and When to Use It.

End of Series:
This post concludes The Next Level Detox Series — your six-part guide to understanding how testing works, what affects your results, and how to prepare responsibly.

Level up your awareness. Knowledge is power — and the safest way to stay in control.