Innovative Diagnostic Methods in Drug Abuse Testing: Comparing Hair, Urine and Saliva Drug Testing

The legalization of cannabis is changing the way we think about drug testing¹ as it leads to higher demands on drug screening technology. In this article, we’ll compare the benefits and limitations of hair, urine and saliva drug testing.

Employers and regulators are increasingly comparing traditional drug tests (such as hair and urine) with emerging non‐invasive methods (such as saliva/oral fluid).¹ 

Each testing method has a distinct detection window. For example:² 

• A drug test using hair can detect marijuana exposure up to about 90 days after use. 
• In comparison, saliva drug testing only picks up very recent use (typically 1–24 hours after consumption).
• Urine tests fall in-between (roughly 1–3 days for moderate use, up to a month for heavy use).

The infographic below summarizes the key advantages and limitations of these three types of drug tests.^2-4

Read more:

Legalized Marijuana is Changing How We do Drug Tests

The Shift to Saliva Testing

Technological advancements: Real-time and multiplex assays

The drugs of abuse testing field is embracing new biosensor and immunoassay platforms.^5,6

• Some manufacturers are now offering lateral flow multi-drug saliva tests or point-of-care analyzers that detect several substances at once.⁵
• Beyond traditional dipsticks, research prototypes use microfluidic chips and novel readers. Smartphone-based THC immunosensors are an example of how machine learning and imaging can quantify very low levels of THC in saliva onsite.⁶
• Other platforms are being developed to run multiplex panels from one saliva sample, enabling rapid in-field tests for several analytes or biomarkers.⁶

These innovations all rely on high-quality antibodies and reagents. Monoclonal antibodies (mAbs), engineered for high specificity, are the cornerstone of modern assays. Immunoassay reviews note that monoclonal antibodies offer superior sensitivity and reproducibility over traditional polyclonals in lateral-flow drug tests. This is why companies are investing in recombinant antibody technology and multiplex platforms.⁷

Medix Biochemica’s role in next-gen THC assays 

As a leading in vitro diagnostics (IVD) raw materials supplier, Medix Biochemica contributes key components for these advanced tests, including for saliva drug testing. Medix Biochemica has been a pioneer in monoclonal antibody development since the 1970s, with world-leading expertise in producing novel IVD antibodies via hybridoma and phage-display methods.⁸ 

Our R&D also employs state-of-the-art recombinant engineering, rescuing and optimizing antibodies from different species and tweaking their structures for enhanced performance.⁸

In addition, Medix Biochemica offers extensive antibody and antigen reagent libraries for drugs of abuse. For example, our drug screening portfolio includes matched antibody–antigen pairs and conjugates, along with certified biospecimens (THC-positive and -negative) for hair, saliva and urine validation. These reagents help assay developers ensure accuracy and compliance in their next-generation tests.⁹ 

Regulatory landscape and compliance trends

Evolving marijuana laws have forced regulators to update drug testing rules. 

However, federal changes are currently being proposed. The U.S. Drug Enforcement Administration (DEA) has been considering rescheduling THC to Schedule III. If this happens, it could affect DOT regulations, but no changes are finalized yet. Industry stakeholders are watching these developments closely.¹¹

Meanwhile, DOT has already modernized its protocols: saliva drug testing was formally added to Regulation 49 CFR Part 40 in late 2024.¹² This means that, once the U.S. Department of Health and Human Services (HHS) certifies laboratories for saliva testing, employers will have an official saliva-based DOT test option. Industry insiders note that this is a major shift – one DOT compliance webinar even called the adoption of oral fluid testing a “whirlwind” change for drug programs. Implementation is pending, but companies are already preparing.¹³

Saliva testing will be especially important for scenarios requiring observed collection where urine collection can be problematic, e.g. testing of transgender or non-binary employees.¹¹

Several other 2024–25 updates also affect testing programs. DOT agencies released 2025 random testing rates and the Federal Motor Carrier Safety Administration (FMCSA) introduced new Clearinghouse rules for drug/alcohol records, requiring the use of electronic reporting forms. Experts are warning employers to stay informed.¹³ 

As assays become multiplexed and real-time, having a supplier with a broad, high-quality antibody portfolio (including saliva/hair controls) is invaluable for manufacturers. This is where partnering with Medix Biochemica can help you take your assays to the next level.

Download Medix Biochemica’s DOA catalog to find out what we can do for you.

With 40 years of experience and a passion for delivering results, our team is here to guide you every step of the way.

Let’s start a conversation!

References:

1. Legalized marijuana is changing how we do drug tests. Medix Biochemica blog. Accessed August 4, 2025. https://articles.medixbiochemica.com/legalized-marijuana-is-changing-how-we-do-drug-tests. 
2. How long does marijuana stay in your system? Blood, urine, and hair. Accessed August 4, 2025. https://www.medicalnewstoday.com/articles/324315.
3. Treatment C for substance abuse. Appendix B. Urine collection and testing procedures and alternative methods for monitoring drug use. In: Substance Abuse: Clinical Issues in Intensive Outpatient Treatment. SAMHSA (US); 2006. Accessed August 4, 2025. https://www.ncbi.nlm.nih.gov/books/NBK64092/.
4. Advantages and disadvantages of drug-testing specimens. National Drug Court Institute. 2021. Accessed August 4, 2025. https://ocfcpacourts.us/wp-content/uploads/2021/05/Advantages-and-Disadvantages-of-Drug-Testing-Specimens.pdf.
5. Multi-drug saliva test cup. BTNX Inc. Accessed August 4, 2025. https://www.btnx.com/product/saliva-drug-test-cup.
6. Liang Y, Zhou A, Yoon JY. Machine learning-based quantification of (–)-trans-Δ-Tetrahydrocannabinol from human saliva samples on a smartphone-based paper microfluidic platform. ACS Omega. 2022 Aug 15;7(34):30064-30073. doi: 10.1021/acsomega.2c03099. 
7. Qriouet Z, Cherrah Y, Sefrioui H, et al. Monoclonal antibodies application in lateral flow immunochromatographic assays for drugs of abuse detection. Molecules. 2021 Feb 18;26(4):1058. doi: 10.3390/molecules26041058.
8. Our science. Medix Biochemica - about us. Accessed August 4, 2025. https://www.medixbiochemica.com/about-us/our-science.
9. Monitor drugs of abuse with Medix Biochemica. 2bscientific. Accessed August 4, 2025. https://www.2bscientific.com/suppliers/medix-biochemica/monitor-drugs-of-abuse-with-medix-biochemica.
10. DOT "recreational marijuana" notice. U.S. Department of Transportation. Accessed August 4, 2025. https://www.transportation.gov/odapc/dot-recreational-marijuana-notice.
11. 2024 transportation compliance: THC, DOT testing, fines. DISA. Accessed 4 August, 2025. https://disa.com/news/2024-transportation-compliance-thc-dot-testing-fines/.
12. Part 40 final rule - DOT summary of changes. U.S. Department of Transportation. Accessed August 4, 2025. https://www.transportation.gov/ODAPC/Notice_Summary_Nov_2024.
13. On-demand webinar: DOT drug testing in 2025: what to expect & how to prepare. Accessed August 4, 2025. https://www.foley.io/webinars/drug-alcohol-testing-trends.
14. How long does marijuana (weed) stay in your system? American Addiction Centers. Accessed August 4, 2025. https://americanaddictioncenters.org/marijuana-rehab/how-long-system-body.