Quick answer: A breathalyzer for alcohol estimates blood alcohol concentration (BAC) from a breath sample and reports it in g/dL (grams per 210 liters of breath). It detects current impairment risk, not past use. DOT acts at 0.02 and treats 0.04 or higher as a positive under 49 CFR Part 40. American Screening Corp supplies wholesale.
- Breath testing shows alcohol in the body now, usually for a few hours after drinking. It does not show use from earlier days.
- DOT-regulated testing requires an evidential breath testing device (EBT) on the NHTSA Conforming Products List and a trained breath alcohol technician.
- Any positive screen is preliminary. Confirm it with an evidential test or laboratory testing, per your policy.
What does a breathalyzer for alcohol detect?
A breathalyzer detects ethanol in deep-lung breath. It converts the reading to an estimated BAC. Results are reported in g/dL, for example 0.04, rather than in ng/mL as urine drug panels are.
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Breath alcohol tracks what is in the blood at that moment. As of the NHTSA page "Drunk Driving", 0.08 g/dL is the per-se limit for drivers 21 and older in nearly every state. Commercial drivers and safety-sensitive employees are held to lower federal thresholds.
What cutoffs apply in workplace and court testing?
Your cutoff depends on who you test. Check the rule that governs your program before you buy a device.
- 0.02 to 0.039 BAC: Under 49 CFR Part 40, a DOT employee must be removed from safety-sensitive duty temporarily. This is not a violation.
- 0.04 or higher: This is a positive DOT alcohol result and requires a confirmation test.
- Non-DOT programs: Employers, probation offices and treatment centers set their own written cutoffs. Many use 0.02 as zero-tolerance or 0.04 to mirror DOT.
Screening versus evidential breathalyzers: which do you need?
A screening device gives a fast, preliminary reading. An evidential device is built to produce a result that can be defended. It records the result, supports a confirmation test and meets federal device requirements.
| Type | Best for | Defensible for DOT? | Typical next step on a positive |
|---|---|---|---|
| Personal or screening breathalyzer | Clinic check-ins, treatment programs, internal policy checks | No, unless it appears on the NHTSA list and is used per Part 40 | Retest or send for evidential or lab confirmation |
| Evidential breath testing device (EBT) | DOT-regulated employers, courts, probation | Yes, if on the NHTSA Conforming Products List and operated by a trained technician | Confirmation test at 0.02 or higher |
| Urine EtG test | Monitoring recent drinking, including abstinence programs | Not a DOT breath test | Confirm by GC/MS or LC-MS/MS laboratory testing |
How long after drinking can a breathalyzer detect alcohol?
A breathalyzer detects alcohol while it remains in the body, which is typically hours after the last drink. The window depends on how much was consumed, body size, food and time. Part 40 also requires a wait of at least 15 minutes before a test to reduce mouth-alcohol error.
If your program needs to know about drinking over the past one to several days, breath is the wrong tool. Pair it with urine EtG testing. Browse our drug test cups for programs that combine drug and alcohol monitoring.
How do you run a breath alcohol test correctly?
- Confirm the device is on the NHTSA Conforming Products List if the test is DOT-regulated.
- Verify the person's identity and explain the procedure.
- Wait at least 15 minutes after any suspected recent drink, and do not let the person eat, drink or smoke during that time.
- Use a new mouthpiece and follow the device prompts for a full, steady exhale.
- Record the displayed result, time and device serial number.
- If the result is 0.02 or higher on a screening test, proceed to the confirmation test within the Part 40 window.
Buyer checklist before you order
- Define the program: DOT, court-ordered, treatment or employer policy.
- Write your cutoff and your action for each result tier.
- Check the device listing and calibration schedule in the manufacturer's instructions.
- Plan for mouthpieces, batteries and calibration supplies, not just the unit.
- Assign a trained operator and a documented chain of record.
- Choose a confirmation path for every positive result.
- Ask about volume pricing and shipping for multi-site rollouts.
What do we hear from buyers?
Clinics, probation offices and staffing firms most often ask whether one device can serve both internal screening and DOT work. It usually cannot. Part 40 testing has its own device and personnel rules, so we recommend separating the two use cases at purchase. Contact our team through the American Screening Corp contact page and we will match supplies to your program. Employers who also need pre-hire checks can use our sister division, Reveal Background.
Regulatory and clearance status
Breath devices are not CLIA-waived urine or oral fluid tests, and we do not describe them as such. Confirm each device's listing and any FDA status against the product record before you rely on it. Every positive screen is preliminary; confirm by GC/MS or LC-MS/MS laboratory testing or an evidential breath test as your program requires.
Frequently asked questions
What is a breathalyzer for alcohol?
It is a device that measures ethanol in exhaled breath and estimates BAC in g/dL. It shows current alcohol in the body, not past use.
What BAC is a positive under DOT rules?
Under 49 CFR Part 40, 0.04 or higher is a positive. A result of 0.02 to 0.039 requires temporary removal from safety-sensitive duty.
Can a screening breathalyzer be used for DOT testing?
Only if it appears on the NHTSA Conforming Products List and is used under Part 40 procedures by a trained technician. Otherwise, use it for non-DOT screening.
How long does alcohol show on a breath test?
Typically a few hours after drinking, depending on the amount, body size and time. Use urine EtG testing for recent drinking over a longer window.
Sources
- eCFR: 49 CFR Part 40, Procedures for Transportation Workplace Drug and Alcohol Testing Programs
- U.S. DOT Office of Drug and Alcohol Policy and Compliance
- NHTSA: Drunk Driving
This article is general information, not legal or medical advice.
