A breathalyzer (evidential breath testing device) measures current breath alcohol concentration at the moment of the test and is the only method DOT accepts for a confirmation result. Saliva alcohol screens give a fast preliminary reading and are DOT-permitted for the screening step only. Urine EtG tests detect a metabolite of alcohol that can show up one to two days after drinking, so they indicate past exposure, not current impairment, and are not part of DOT testing.
For a buyer stocking a testing program, the right method depends on whether you are regulated by DOT, what question you are actually trying to answer (right now versus recent days), and whether you need a device with a specific technician and paperwork chain behind it. Here is how the three methods compare and where each one fits.
What Each Method Actually Measures
Evidential breath testing (EBT / breathalyzer)
An evidential breath testing device estimates blood alcohol concentration from a deep-lung breath sample at the time of the test. It answers one question: what is this person's breath alcohol level right now. Under DOT rules, an EBT is the only device permitted to run a confirmation test, and it must appear on the U.S. Department of Transportation's list of approved evidential breath measurement devices referenced in 49 CFR 40.231.
Saliva alcohol screens
A saliva (oral fluid) alcohol screen uses a device or pad that reacts to alcohol present in oral fluid. It is fast and easy to administer in the field, which is why it shows up in non-DOT workplace programs, roadside and post-accident checks, and as a first-step screening option in some regulated programs. Under DOT rules, a saliva alcohol screening device (ASD) is a permitted screening tool, listed by name in 49 CFR 40.245, but it cannot be used to confirm a result.
Urine EtG (ethyl glucuronide)
EtG is not a measurement of alcohol itself. It is a minor, direct metabolite that forms when the body breaks down ethanol, and it is usually measured in urine. According to SAMHSA's 2012 Advisory on alcohol biomarkers, EtG and its companion marker ethyl sulfate (EtS) "may become positive shortly after even low-level exposure to alcohol and may remain detectable in urine for 1 to 2 days," which makes EtG useful for abstinence monitoring rather than a same-day impairment reading (SAMHSA, The Role of Biomarkers in the Treatment of Alcohol Use Disorders, 2012 Revision). The same advisory notes the test's high sensitivity is also its weakness: everyday products like alcohol-based hand sanitizer and mouthwash can produce a positive result, so SAMHSA states biomarkers, including EtG, "should not be used as the sole screening tool."
Method Comparison at a Glance
| Method | What it measures | Typical detection window | DOT status | Best fit |
|---|---|---|---|---|
| Breathalyzer (EBT) | Breath alcohol concentration at time of test | Current reading only, hours as alcohol clears | Required for confirmation; also usable for screening | DOT confirmation tests, on-site current-impairment checks |
| Saliva alcohol screen | Alcohol present in oral fluid | Roughly the same short window as breath, current use | Permitted for screening only, never confirmation | Non-DOT screening, post-accident and reasonable-suspicion checks, DOT screening step |
| Urine EtG | A metabolite formed after the body processes alcohol | Roughly 1 to 2 days after exposure | Not part of DOT alcohol testing | Non-DOT abstinence monitoring, recovery and probation-style programs |
DOT Alcohol Testing: What the Rule Actually Requires
DOT-regulated alcohol testing runs on 49 CFR Part 40, Subparts L and M, and it has a specific two-step structure. A screening test can be conducted with an EBT, a non-evidential breath ASD, or a saliva or breath-tube ASD, per 49 CFR 40.229. If that screening result comes back at 0.02 or higher, the technician must direct the employee to a confirmation test, per 49 CFR 40.247. That confirmation test must be run on an EBT drawn from ODAPC's approved evidential breath measurement device list, and no other device qualifies, per 49 CFR 40.231. Confirmation must start within 30 minutes of the screening test, following a required waiting period, per 49 CFR 40.251.
Both steps require a trained operator. A Breath Alcohol Technician (BAT) runs confirmation tests and can also run screening tests; a Screening Test Technician (STT) can run screening tests only. Both must complete a qualification course, demonstrate error-free proficiency on the exact device they use, and refresh their training at least every five years, per 49 CFR 40.213. Note that Part 40 sets these testing procedures; consequences for a given result, such as removal from safety-sensitive duty, are set by the DOT agency rule that applies to your operation (for example, FMCSA's rules for motor carriers), not by Part 40 itself.
For buyers building or restocking a DOT program, our DOT drug and alcohol testing collection is organized around this screening-then-confirmation structure.
Where Saliva Screens Fit
Saliva alcohol screens earn their place on the shelf because they are fast, disposable, and simple to administer without special equipment. For non-DOT employers, a saliva screen is often the entire program: a quick check for reasonable suspicion, post-accident response, or random testing, with a policy that defines what happens next if the result is non-negative. For DOT-covered employers, a saliva ASD can be the screening step, but it can never stand in for the EBT confirmation test once a screening result hits 0.02 or higher. Buyers can browse current options in our alcohol tests collection.
Where EtG Fits, and Where It Doesn't
EtG earns its place in a different kind of program: one built around abstinence over days, not impairment in the moment. SAMHSA's advisory describes EtG's practical use in monitoring individuals who are required to stay alcohol-free, including people in recovery programs, court-ordered monitoring, and safety-sensitive licensure situations where any drinking is a violation of an agreement. Because the window runs one to two days, an EtG test can catch drinking that happened well before a scheduled check-in, something a breathalyzer or saliva screen cannot do since both only reflect alcohol present at the moment of the test.
What EtG cannot do is answer the DOT question or the "is this person impaired right now" question. It is not on DOT's list of permitted screening or confirmation devices, and a positive result does not establish blood alcohol level or current impairment, only that alcohol exposure occurred at some point in the prior day or two. SAMHSA's own advisory is explicit that its guidance does not even cover breath or saliva alcohol measurement, underscoring that EtG is a separate tool for a separate use case, not a substitute for evidential breath testing.
Choosing the Right Method for Your Program
- DOT-regulated operation: stock EBTs from the approved list for confirmation, and decide whether screening will run on the same EBT or a separate breath or saliva ASD, plus a trained BAT and STT.
- Non-DOT workplace, current-impairment focus: a breathalyzer or saliva screen answers "right now," with saliva often preferred for speed and low training overhead.
- Recovery, probation-style, or abstinence-monitoring program: EtG fits when the question is "has this person had any alcohol in the last day or two," paired with a policy that treats a positive result as one data point, not standalone proof, consistent with SAMHSA's caution against using it alone.
- Mixed programs: many employers stock both a breath or saliva method for same-day checks and, separately, EtG for abstinence agreements, since the two answer different questions.
Compliance and Accuracy Notes
All alcohol screening devices, including breath, saliva, and EtG methods, are screening tools. A non-negative or elevated screening result is preliminary and should be confirmed and interpreted by a qualified technician, medical review officer, or program administrator under your written policy before any employment decision is made. No device diagnoses alcohol use disorder or proves who consumed a substance; it indicates the presence of alcohol or a related marker in a sample. DOT program administrators should always confirm current device approval status and procedural requirements directly against 49 CFR Part 40 before building or updating a testing program.
Frequently Asked Questions
Does DOT allow saliva alcohol tests?
Yes, but only for the screening step. A saliva ASD can be used to screen for alcohol under 49 CFR 40.245. If that screening result is 0.02 or higher, DOT rules require a confirmation test on an EBT; a saliva device cannot be used to confirm a result.
What is the difference in detection window between a breathalyzer and an EtG test?
A breathalyzer reads breath alcohol concentration at the moment of the test, so it reflects alcohol currently in the body. A urine EtG test can stay positive roughly one to two days after alcohol exposure, per SAMHSA's 2012 biomarker advisory, so it reflects recent exposure rather than a current reading.
Is EtG testing DOT-approved?
No. DOT alcohol testing under 49 CFR Part 40 recognizes only evidential breath testing devices for confirmation and breath or saliva alcohol screening devices for screening. EtG is not on either approved device list and is not part of the DOT alcohol testing process.
Who is allowed to run a DOT alcohol test?
A Breath Alcohol Technician (BAT) is required to run confirmation tests and may also run screening tests. A Screening Test Technician (STT) may run screening tests only. Both must complete DOT-recognized qualification training and demonstrate error-free proficiency on the specific device used, per 49 CFR 40.213.
Does a positive EtG result prove someone was drinking?
Not by itself. SAMHSA's advisory states that because EtG is highly sensitive, exposure to alcohol in everyday products such as hand sanitizer or mouthwash can also produce a positive result, so a positive EtG test should not be used as the sole basis for a decision.
Can an EtG test tell if someone is impaired right now?
No. EtG measures a metabolite that can persist for roughly one to two days after alcohol exposure. It does not indicate a blood alcohol level or current impairment the way a breathalyzer does.
Further Reading
Ready to stock breath, saliva, or EtG options for your program? See our breathalyzer collection and alcohol tests collection for current wholesale options.
