The incident report on the HR manager's desk runs to three paragraphs. A loader on the evening shift was "unsteady", a supervisor "smelled something", the man was sent home, and the shift ran short-handed. Nowhere in the report is there a number. When the worker's union representative asks what the reading was, there is no answer, because no BAC level test was ever run.
That gap is the whole problem. Without a measured result, the company has an accusation it cannot support and the worker has a grievance it cannot disprove. A BAC test converts a judgement call into a record. It is the difference between a decision you can defend and one you will spend three weeks arguing about.
This is the case for treating alcohol screening as a routine operating control rather than a reaction to suspicion, and for knowing which test answers which question.
What a BAC level test actually measures
BAC stands for blood alcohol concentration: the amount of ethanol in the bloodstream, expressed in India as milligrams per 100 millilitres of blood. It is a snapshot of the present moment, not a history. A BAC level test tells you what is circulating right now and, by extension, whether the person in front of you is fit to drive a truck, operate a forklift or enter a confined space.
A breathalyzer test reaches that number indirectly. Alcohol in the blood passes into the air in the deep lungs at a stable, known ratio, so a breath sample from the end of a full exhalation can be converted into an equivalent blood concentration. That is why a breath analyser is a practical screening instrument: it produces a defensible figure in seconds without a needle, a nurse or a laboratory.
For a fuller treatment of how the reading is derived and where the margins sit, see Breathalyzer Test: How It Works, Accuracy and BAC Limits in India.
The four tests people confuse with each other
Most disputes about an "alcoholic test" come from someone using the wrong test for the question they are asking. Each method has a different window and proves a different thing.
Test Sample What it proves Practical window
Breath analyser Deep-lung breath Current impairment-level BAC Minutes to a few hours after drinking
Blood test Venous blood Current BAC, evidential grade Same as breath, requires clinical setting
EtG test Urine (usually) Alcohol was consumed recently Roughly one to three days
PEth test Blood Sustained or repeated drinking Weeks
An EtG test detects a metabolite, not alcohol. It can flag drinking that happened the previous evening in someone who is now entirely sober, which makes it useful for abstinence monitoring and useless for a gate check. A PEth test looks further back still and speaks to a pattern of consumption over weeks, which is a clinical or rehabilitation question, not a shift-start question.
If your policy question is "is this person fit to work in the next eight hours", breath is the right instrument. Breathalyzer Test vs Other Alcohol Tests: What Each One Proves sets the comparison out in more detail, and Blood Alcohol Level Test: What It Proves and When You Need One covers when escalation to blood is warranted.
The "sober test" problem
Walk-the-line checks, finger-to-nose, counting backwards: these are field observations, not measurement. A supervisor performing an informal sober test is describing behaviour, and behaviour has many causes. Fatigue after a double shift, low blood sugar, an inner-ear problem, prescription medication and heat stress all look like a drunk test failure from ten feet away.
The reverse is equally true. Habitual drinkers can present as steady and articulate at a BAC well above the legal limit. A drunk test based on appearance will miss exactly the people most likely to be operating machinery while over the line.
This is why observation should trigger a BAC level test, never replace it. Observation is the reason to test. The test is the finding.
The Indian limit, and why your workplace limit is lower
Under the Motor Vehicles Act, driving in India with more than 30 mg of alcohol per 100 ml of blood is an offence. That is the threshold a traffic drunk driving test is checked against on the road, and it is strict by international standards.
A workplace does not have to adopt that figure. Most Indian industrial and fleet policies set a zero-tolerance standard, meaning any detectable reading disqualifies the person from safety-critical duty for that shift. Zero is easier to administer, easier to explain and removes arguments about whether someone was "only slightly" over.
Zero on a display does not mean zero alcohol in the body in an absolute laboratory sense; it means nothing detectable above the instrument's threshold. That distinction matters when a reading is challenged, and it is worked through in Alcohol Breath Test Normal Range: What Zero Actually Means.
For transport operators the two limits converge in a useful way. If your drivers clear an internal zero-tolerance check at dispatch, they will clear a roadside driving drunk test as well. The internal test protects the driver, the load, the other road user and your insurance position simultaneously.
Why a breathalyzer test online is not a test
Search for a breathalyzer test online and you will find calculators that ask for body weight, number of drinks and hours elapsed, then return an estimated BAC. These are teaching tools. They are not measurement, and no policy decision should rest on one.
The estimate cannot know your drink strength, your pour size, what you ate, your liver function, your medication or your actual elimination rate. Two people of identical weight drinking identically can sit at meaningfully different readings two hours later. An online estimate that says you are fine is not a defence at a checkpoint and not a defence in a disciplinary hearing.
The only reliable answer comes from a sample. Either breath into a calibrated instrument or blood into a laboratory tube.
What a workable screening policy looks like
A BAC level test is only as strong as the process around it. The device produces a number; the procedure is what makes the number stick.
• Write the rule before you need it. Who is tested, when, at what threshold, and what happens at a positive reading. Circulate it, have it acknowledged, include it in induction.
• Test by schedule, not by suspicion. Random or universal checks at shift start remove the accusation of targeting. Suspicion-based testing alone invites a bias complaint.
• Wait fifteen minutes before the first sample. Mouth alcohol from a recent drink, mouthwash or certain medicines can inflate a reading. A short wait and a rinse with water removes the most common challenge.
• Always offer a confirmatory retest. A second sample after a few minutes on the same device, or escalation to a blood test at a hospital, is what turns a screening result into a defensible finding.
• Log everything. Time, device serial number, last calibration date, operator name, both readings, and the tested person's signature.
• Calibrate on schedule. Sensors drift. An uncalibrated instrument is the first thing a competent representative will attack, and the attack usually succeeds.
The BAC Test That Holds Up: Procedure, Records and Defending a Result goes deeper on documentation, and BAC Testing Explained: What the Reading Means and Why It Holds Up covers how to interpret borderline numbers without overreaching.
Choosing the instrument for the job
Match the device to the volume and the stakes. A fuel-cell sensor is the right choice wherever a reading may be disputed: it responds to ethanol specifically and holds accuracy across repeated use, which matters at a gate screening sixty people an hour. Semiconductor units are cheaper and suit low-volume, low-consequence checks such as a household car or a small office.
For high-throughput entry screening, a non-contact or passive-mode unit lets you clear a queue quickly and pull anyone who flags into a full mouthpiece test. For fleet dispatch, choose a unit that prints or exports readings so the record exists without anyone retyping it. BAC Tester: What It Measures, What It Proves, and How to Use One and Breathalyser Test: What It Measures, What It Proves, and When to Run One cover the selection criteria in full.
Whatever you buy, budget for mouthpieces and for annual calibration from the start. A device nobody has recalibrated in eighteen months is worse than no device, because it produces numbers that feel authoritative and will not survive scrutiny.
Who carries the consequence
When screening is skipped and something goes wrong, the question asked afterwards is never "did the supervisor have a hunch". It is "what was your control, and can you show it was working that day". That question lands on the safety lead, the transport manager, the site in-charge and eventually the directors.
A BAC level test is a small, fast, inexpensive control that answers it directly. The decision in front of you is not whether alcohol screening is reasonable. It is whether you would rather have a number in the log or a paragraph of opinion in an incident report.