What a DOT drug test tests for, and what it does not

A DOT drug test checks for five drugs or drug classes listed in 49 CFR 40.82: marijuana metabolites, cocaine metabolites, amphetamines, opioids and phencyclidine (PCP). The laboratory is forbidden to test a DOT specimen for anything else. Alcohol is tested separately by breath, and as of the eCFR text dated 23 September 2026 fentanyl is not yet on the DOT panel, although DOT proposed adding it in September 2025.

This page covers what is tested. When and who is tested is on the DOT drug and alcohol testing rules page, and the random testing percentages are on random testing rates.

The five classes, and why people call it a "5-panel"

Section 40.82 says a laboratory must test for these five drugs or classes in a DOT drug test and must not test DOT specimens for any other drugs:

1. Marijuana metabolites (40.82(a)).
2. Cocaine metabolites (40.82(b)).
3. Amphetamines (40.82(c)).
4. Opioids (40.82(d)).
5. Phencyclidine (PCP) (40.82(e)).

Each class covers more than one substance. The cutoff tables in 40.85 (urine) and 40.91 (oral fluid) show exactly which analytes the laboratory looks for. Under Part 382 the term "controlled substances" for truck and bus drivers is defined by reference to this list: 382.107 says controlled substances "mean those substances identified in 40.82".

At the collection site

Most of what drivers remember about a DOT test is the collection, and Part 40 scripts nearly every step of it.

• Identification. Under 40.61(c) the collector must see a photo ID issued by the employer or by a federal, state or local government, such as a driver's license. Faxes and photocopies are not accepted. An owner-operator's own company ID does not count.
• Outer clothing and pockets. 40.61(f) requires you to remove outer clothing such as a jacket or hat and leave bags behind, and to empty your pockets for inspection. You keep your wallet. The collector may not ask you to remove other clothing, and may not ask you to change into an examination gown unless the collection is being done together with a DOT-authorized medical examination.
• Medications. Under 40.61(g) the collector must tell you not to list your medications on the custody and control form. Medications are discussed with the MRO, and only if the laboratory reports a non-negative result.
• Hands and water. You wash and dry your hands first and get no further access to water (40.63(b)).
• Volume and temperature. The specimen must be at least 45 mL (40.65(a)). The collector reads the temperature strip within four minutes; the acceptable range is 32 to 38 °C, or 90 to 100 °F (40.65(b)). Out of range means an immediate new collection under direct observation or an oral fluid collection (40.65(b)(5)).
• Observed collections. Return-to-duty and follow-up tests are always directly observed (40.67(b)), and a specimen that shows signs of tampering means an immediate new collection under direct observation or by oral fluid (40.65(c)(1)). The observer must be the same sex as the employee (40.67(g)).
• Alcohol first. If you are having both tests, 40.61(b)(1) says the alcohol test should, as far as practicable, be finished before the drug collection starts.

Leaving before the process is complete, failing to cooperate, or refusing to empty your pockets can each be a refusal under 40.191(a), except that leaving before a pre-employment collection has started is not.

Urine cutoffs

A laboratory first runs an initial test. Under 40.85(b), a result below the initial cutoff is reported negative; at or above it, the laboratory must run a confirmation test. Under 40.85(c), a confirmation result below its cutoff is negative and at or above it is a confirmed positive. The table below is from 40.85(a), in nanograms per milliliter.

A footnote to the table allows a laboratory using an alternate technology initial test for THCA or benzoylecgonine to use the confirmation cutoff (15 and 100) for both steps.

Oral fluid: in the rule, not yet in practice

Part 40 also authorizes oral fluid testing, with its own cutoffs in 40.91 (for example 4 ng/mL initial and 2 ng/mL confirmation for THC). But 40.67(g)(5) says an employer may use oral fluid only when there are at least two HHS-certified oral fluid laboratories. In its final rule published on 11 May 2026 (91 FR 25507, effective 10 June 2026), DOT stated that there were currently no HHS-certified oral fluid laboratories. Check for an HHS notice before assuming oral fluid tests are being run.

Validity testing: the other thing the lab checks

Every urine specimen is also checked for tampering. 40.86 requires validity testing; 40.87 requires creatinine, pH and oxidizing adulterant tests on each specimen. Under 40.88, a specimen is dilute when creatinine is at least 2 but under 20 mg/dL and specific gravity is above 1.0010 but below 1.0030, and substituted when creatinine is under 2 mg/dL and specific gravity is at or below 1.0010 or at or above 1.0200. The consequences differ:

• A positive-dilute result is treated as a verified positive (40.197(a)).
• A negative-dilute result with creatinine from 2 to 5 mg/dL means an immediate recollection under direct observation (40.197(b)(1)). Above 5 mg/dL the employer may, but need not, retest (40.197(b)(2)).
• A verified adulterated or substituted result counts as a refusal to test (40.191(b)).

What the DOT test does not look for

Alcohol

The urine specimen is not tested for alcohol, because alcohol is not on the 40.82 list and 40.13(c) forbids other tests on DOT specimens. DOT alcohol tests use devices on ODAPC's approved lists: 40.229 allows screening with an approved screening device or an evidential breath testing device (EBT), and 40.231 allows only EBTs for confirmation. The limits come from Part 382: 382.201 bars duty at 0.04 or more, and under 40.23(c) a result of 0.02 to 0.039 means temporary removal as the DOT agency rules provide.

Fentanyl, for now

HHS added fentanyl and norfentanyl to the federal employee testing panel effective 7 July 2025 (90 FR 4662), with a 1 ng/mL urine cutoff, and republished the same panel on 13 March 2026 (91 FR 12308). DOT proposed adding fentanyl to its own panel on 2 September 2025 (90 FR 42363). As of the eCFR text dated 23 September 2026, 40.82 and 40.85 do not include it. When DOT adopts a final rule, this page will change.

Everything else

Benzodiazepines, barbiturates, tramadol, gabapentin, kratom, psilocybin mushrooms, synthetic cannabinoids and most other substances are not DOT analytes, and 40.82 forbids testing a DOT specimen for them. That does not make them allowed. Separate rules still apply:

• 382.213(a) bars reporting for or staying on duty when a driver uses any Schedule I substance, and 392.4(a)(1) bars being on duty while possessing, using or being under the influence of one. Psilocybin is in Schedule I (21 CFR 1308.11(d)), and so are some kratom-derived compounds, such as mitragynine pseudoindoxyl, that DEA has placed there.
• 382.213(b) and 391.41(b)(12)(ii) allow other controlled substances only when prescribed by a licensed medical practitioner who knows the driver's history and has advised that the drug will not affect safe driving. See which medications CDL drivers can take.
• 392.4(a)(4) bars being on duty under the influence of any other substance to a degree that makes the driver incapable of driving safely.

Hair tests are not DOT tests

Some carriers run hair tests on applicants. Those are company tests, not DOT tests. 40.13(a) requires DOT tests to be completely separate from non-DOT tests in all respects, and 40.13(b) requires the DOT test to be completed first, with a separate urine void for any non-DOT urine test. Under 40.191(e), refusing a non-DOT test is not a refusal of a DOT test and has no consequences under DOT rules. The carrier can still apply its own hiring policy.

How a result becomes "positive"

1. Laboratory. Initial test, then confirmation for anything at or above the initial cutoff (40.85(b) and (c)). The laboratory reports only to the Medical Review Officer (MRO), never to the employer directly (40.97(c)).
2. MRO interview. For marijuana, cocaine, amphetamines, semi-synthetic opioids and PCP, 40.137(a) requires the MRO to verify a confirmed positive unless the driver presents a legitimate medical explanation, such as a legally valid prescription consistent with the Controlled Substances Act. The driver carries the burden of proof (40.137(c)).
3. Codeine and morphine have their own rule in 40.139: 6-AM is always verified positive; codeine or morphine at or above 15,000 ng/mL in urine is positive unless there is a legitimate medical explanation, and poppy seeds do not count as one; below that level the MRO verifies positive only with clinical evidence of unauthorized use.
4. Explanations the MRO must reject are listed in 40.151, including passive-ingestion stories, a physician's recommendation of a Schedule I drug under a state medical marijuana law, and use of hemp or CBD products (see marijuana, CBD and the CDL).

Example: two opioid results

Illustration only; the concentrations are invented to show how 40.139 sorts results. Driver A's urine confirms codeine at 3,000 ng/mL with no 6-AM. That is above the 2,000 confirmation cutoff but below 15,000, so under 40.139(c) the MRO may verify it positive only if there is clinical evidence of unauthorized opiate use, such as signs of intoxication or a recent history of misuse. With no such evidence, the MRO must verify it negative. Driver B's result shows morphine at 18,000 ng/mL. Under 40.139(b) that is verified positive unless Driver B shows a legitimate medical explanation, and eating poppy seeds is not one.

After a failed test

• The employer removes the driver from safety-sensitive work on the first report of a verified positive, without waiting for the written report or a split specimen result (40.23(a)).
• 382.215 bars the driver from duty after a positive, adulterated or substituted result.
• The driver cannot return until completing the return-to-duty process in Part 40, Subpart O (40.23(d)).
• The violation goes into the Drug and Alcohol Clearinghouse. When the Clearinghouse tells a state that a driver is prohibited under 382.501(a), the state must start downgrading the CLP or CDL and finish within 60 days (383.73(q)). How employers query the Clearinghouse is on Clearinghouse queries.

Do CDL schools or permits require a drug test?

The federal test attaches to an employer, not to a license. 382.301 requires a verified negative pre-employment test before a driver first performs safety-sensitive functions for an employer. The list of what a state must do before issuing a commercial learner's permit, in 383.73(a), does not include a drug test, but since 18 November 2024 it does include a Clearinghouse query: a state that is told the applicant is prohibited under 382.501(a) must not issue, renew or upgrade the permit (383.73(a)(8)). Schools and carrier-run programmes often test anyway as their own policy.

Common misunderstandings

• "It is not on the panel, so I can take it." Schedule I substances are banned by 382.213(a) and 392.4 whether or not the lab looks for them.
• "My doctor's test was clean." 40.13(f) and 40.151(a) bar anyone from changing a DOT result based on a non-DOT test.
• "I will drink a lot of water first." Dilution is measured; a negative-dilute at 2 to 5 mg/dL creatinine means an observed recollection.
• "A hair test fail means a DOT violation." It is a company matter, not a DOT result, under 40.13.