Does CBD Show Up on Drug Tests in NZ? What You Need to Know

As CBD products grow in popularity across New Zealand, one of the most common questions we hear from patients is:

“Will CBD show up on a drug test?”

The short answer? CBD itself isn’t typically tested for, but some CBD products contain trace amounts of THC, which can cause a positive result in certain situations. In this guide, we’ll break down how drug testing works, the role of THC in CBD products, and what you need to know if you’re using medicinal cannabis under prescription.

Contents

• How Drug Testing Works
  
  
• Types of CBD and Testing Risk
  
  
• NZ Legal Guidelines
  
  
• Factors That Affect Test Results
  
  
• How Long CBD (or THC) Stays in Your System
  
  
• Workplace Testing Considerations
  
  

How Drug Testing Works

Drug tests don’t screen for CBD. They’re typically designed to detect THC or its byproducts. Most tests look for THC-COOH, a metabolite produced when your body processes THC¹.

Common drug testing methods in New Zealand include:

• Urine tests: Most common in workplace settings due to longer detection windows
  
  
• Blood tests: Detect more recent use but have shorter detection timeframes
  
  
• Hair tests: Can show long-term patterns of use
  
  
• Oral fluid tests: Focus on very recent use
  
  

Urine testing remains the most widely used due to its convenience and reliability².

Types of CBD and Testing Risk

CBD is not the target of the test, but some CBD products contain THC, which is. Here’s what to watch for:

• Full-spectrum CBD products contain small amounts of THC (up to 2 percent in New Zealand). These carry the highest risk of triggering a positive result³.
  
  
• Broad-spectrum CBD and CBD isolate products are THC-free, making them much safer choices for people subject to testing⁴ ⁵.
  
  

The initial THC screening threshold is 50 ng/mL in urine. If a sample tests positive, a more sensitive follow-up test confirms it using a threshold of 15 ng/mL⁶.

See our guide on Full Spectrum vs Isolate CBD.

Need help understanding the difference between CBD types? Talk to one of our doctors to find the option that fits your lifestyle.

Book a consultation

NZ Legal Guidelines

CBD is legal in New Zealand by prescription only. All prescribed products must comply with the Medicinal Cannabis Scheme, which includes strict regulations around product quality and THC content⁵.

However, recreational cannabis remains illegal. That includes unauthorised THC-containing CBD products.

Workplace drug testing in New Zealand is not standardised, but many employers test for THC. If you are using medicinal cannabis, we recommend keeping:

• A copy of your treatment plan
  
  
• Proof of your prescription
  
  
• Open communication with your doctor and employer if needed
  
  

If you’re unsure about how drug testing might impact you, our clinical team can help explain your options.

Book a free nurse eligibility call

Factors That Affect Test Results

Even with legal, prescribed use, several factors can influence whether THC shows up in your system:

• Type of CBD product: Full-spectrum means more THC exposure
  
  
• Dose and frequency: Higher or regular use increases risk
  
  
• Your metabolism: Everyone processes cannabinoids differently⁷
  
  
• Test sensitivity: Some labs test at lower thresholds⁸
  
  
• How you take it: Inhaled, ingested, or topical formats absorb differently
  
  
• Passive exposure: Rare, but possible in poorly ventilated areas with smoke⁹

How Long CBD or THC Stays in Your System

While CBD itself isn’t typically screened for, THC metabolites can linger in your system, especially in urine.

Approximate detection windows for THC:

• Occasional use: 3 to 7 days
  
  
• Moderate use: 5 to 10 days
  
  
• Frequent or chronic use: Up to 30 or more days
  
  

In blood, CBD is typically detectable for around 6 hours after a single dose¹0. THC is usually cleared from the blood within a few hours to a couple of days¹1.

Workplace Drug Testing Considerations

If you’re subject to workplace testing or legal compliance:

• Stick to CBD isolate or broad-spectrum products if possible
  
  
• Make sure your product is prescribed and third-party tested
  
  
• Speak to your doctor and consider informing your employer, especially if using full-spectrum products
  
  

Even small amounts of THC can result in a positive test, depending on how sensitive the test is. Understanding your treatment and choosing the right product is key.

Worried About Testing Positive?

You’re not alone. Many patients ask us about this, especially when balancing wellness with work or legal responsibilities.

At Cannabis Clinic, we’re here to help you understand your treatment options and feel confident about your care.

Book a consultation to discuss the best CBD option for your lifestyle and testing needs.

As medicinal cannabis becomes more widely used in New Zealand, staying informed about product types, testing risks, and legal responsibilities is essential, particularly for patients working in safety-sensitive roles or undergoing regular screening.

Let’s find a treatment plan that supports your health and gives you peace of mind.

References

1. Huestis, M. A. (2007). Human cannabinoid pharmacokinetics. Chemistry & Biodiversity, 4(8), 1770–1804.
   
2. Verstraete, A. G. (2004). Detection times of drugs of abuse in blood, urine, and oral fluid. Therapeutic Drug Monitoring, 26(2), 200–205.
   
3. Vandrey, R., et al. (2017). Pharmacokinetics of cannabinoids administered via vaporised cannabis in patients with chronic pain. Clinical Pharmacology & Therapeutics, 102(4), 671–681.
   
4. Citti, C., et al. (2018). Pharmaceutical and biomedical analysis of cannabinoids: A critical review. Journal of Pharmaceutical and Biomedical Analysis, 147, 565–579.
   
5. Bonn-Miller, M. O., et al. (2017). Labeling accuracy of cannabidiol extracts sold online. JAMA, 318(17), 1708–1709.
   
6. Substance Abuse and Mental Health Services Administration. (2017). Mandatory Guidelines for Federal Workplace Drug Testing Programs. Federal Register, 82(13), 7920-7970.
   
7. Grotenhermen, F. (2003). Pharmacokinetics and pharmacodynamics of cannabinoids. Clinical Pharmacokinetics, 42(4), 327–360.
   
8. Milman, G., et al. (2010). Oral fluid and plasma cannabinoid ratios after controlled oral THC. Clinical Chemistry, 56(8), 1261–1269.
   
9. Musshoff, F., & Madea, B. (2006). Biological matrices (urine, blood, hair) as indicators of recent or ongoing cannabis use. Therapeutic Drug Monitoring, 28(2), 155–163.
   
10. Taylor, L., et al. (2018). Safety, tolerability, and pharmacokinetics of highly purified cannabidiol. CNS Drugs, 32(11), 1053–1067.
    
11. Grotenhermen, F. (2003). Review of cannabinoid plasma and tissue pharmacokinetics. Clinical Pharmacokinetics, 42(4), 327–360.