SAMHSA Drug Testing Guidelines

The Substance Abuse and Mental Health Services Administration (SAMHSA) publishes the mandatory guidelines for federal workplace drug testing. These guidelines define the cutoff levels, testing protocols, and laboratory standards that govern cannabis testing in federal and DOT-regulated programs.

Current Guidelines

The current SAMHSA Mandatory Guidelines for Federal Workplace Drug Testing Programs were published at 88 FR 70768 (October 12, 2023) and became effective February 1, 2024. The 2025 update (90 FR 4662, effective July 7, 2025) added fentanyl and norfentanyl to the standard panel.

Primary reference: SAMHSA Drug-Free Workplace FAQs.

The Standard Five-Panel Test

Federal workplace drug testing targets five drug classes:

1. Marijuana (THC-COOH)
2. Cocaine (benzoylecgonine)
3. Opiates (codeine, morphine)
4. Phencyclidine (PCP)
5. Amphetamines (amphetamine, methamphetamine)

Additional analytes have been added over time:

• MDMA/MDA (2010)
• Hydrocodone/Hydromorphone and Oxycodone/Oxymorphone (October 2017)
• 6-acetylmorphine (heroin metabolite)
• Fentanyl/Norfentanyl (effective July 7, 2025)

Full Cutoff Table

All concentrations are in ng/mL unless otherwise specified.

Cannabis Cutoffs in Detail

Cannabis testing uses a two-step process:

1. Initial screen at 50 ng/mL — immunoassay. Any specimen below this cutoff is negative; any at or above goes to step 2.
2. Confirmation at 15 ng/mL — GC-MS or LC-MS/MS. A confirmed positive requires THC-COOH at or above 15 ng/mL in the confirmation test.

The confirmation cutoff is lower than the screening cutoff because confirmation tests are more sensitive and specific. A specimen can screen positive (above 50) but confirm negative (below 15 on GC-MS) in edge cases — this is rare but happens.

Why These Specific Numbers?

The 50 ng/mL screening cutoff was set in the 1980s based on immunoassay sensitivity of that era and has been retained for compatibility. It represents a balance: low enough to catch most cannabis users, high enough to avoid routine positives from secondhand smoke and trace contamination.

The 15 ng/mL confirmation cutoff is based on the sensitivity of GC-MS equipment and the desire for analytical reliability. Below 15 ng/mL, measurement uncertainty becomes significant on GC-MS platforms.

Oral Fluid (Saliva) Cutoffs

SAMHSA's Oral Fluid Mandatory Guidelines (OFMG), effective October 10, 2023:

• Initial screen: 4 ng/mL THC
• Confirmation: 2 ng/mL THC

These are dramatically lower than urine cutoffs because oral fluid concentrations are much lower overall. See Oral Fluid Testing.

Certified Laboratories

Federal workplace drug testing can only be performed by SAMHSA-certified laboratories. The current list is maintained by the National Laboratory Certification Program (NLCP). Certification requires:

• Meeting technical standards for equipment and methodology
• Passing proficiency testing programs
• On-site inspection
• Ongoing quality assurance monitoring

Non-certified labs cannot perform federal or DOT workplace drug testing — though they can perform testing for private employers with lower standards.

Specimen Validity Testing

SAMHSA guidelines require specimen validity testing on every sample:

• Creatinine — 20–400 mg/dL normal; below 20 is dilute, below 2 is substituted
• Specific gravity — 1.003–1.030 normal
• pH — 4.5–8.0 normal
• Oxidants/adulterants — tests for common adulterants

See Hydration and Dilution for detailed discussion of what these tests detect.

Non-Federal Employer Cutoffs

Private employers not subject to federal regulation can use SAMHSA cutoffs or set their own. Common alternatives:

• 20 ng/mL — extends detection window; used by military and some clinical labs
• 100 ng/mL — shortens detection window
• 300 ng/mL — some clinical pain management contexts

Lower cutoffs dramatically extend detection windows for chronic users. At 20 ng/mL, chronic heavy users can test positive for 67–93 days (Huestis). See Chronic Heavy Detection Windows.

Related Reading

• Federal Rules Overview
• DOT Testing
• Urine Drug Testing