top of page
  • Writer's pictureJustin Sparks

How Long Do Breathalyzers Detect Alcohol Poisoning? All You Need to Know

Updated: Nov 8, 2023

A couple of friends went out late one night to binge drink. They slept for around six hours before rushing to work. One friend gets pulled over by the cops for speeding. Will a breathalyzer test detect alcohol if the police officer asks the driver to do one after smelling alcohol on their breath?

Probably. About 24 hours after a person's last alcoholic drink, a breathalyzer will still be able to detect alcohol in their system, and they will be caught for drunk driving.

Despite this, the precise period of time a DUI breath test can detect alcohol will usually vary based on:

  • A person’s system

  • The amount of alcohol the person consumed

How Does a Breathalyzer Detect Alcohol?

How Does a Breathalyzer Detect Alcohol?

A person's breath alcohol concentration is usually measured via breathalyzer tests. Sometimes, the term "BrAC" is used to refer to "breath alcohol content." A breathalyzer turns the BrAC values into BAC values after receiving a breath sample.

When a person drinks alcohol, it enters the small intestine after passing through the digestive tract. The alcohol then enters the bloodstream via diffusion.

Then, the alcohol travels through the person's body until it eventually reaches the lung capillaries. When this driver exhales, the alcohol that has been diffused into their lungs will be released.

Therefore, when the police use a breathalyzer, the machine will pick up the alcohol.

What Does a Breathalyzer Test Measure?

A breathalyzer test essentially measures the blood alcohol content/concentration or BAC.

Blood alcohol content is often expressed as a percentage. The higher the percentage, the higher the BAC will be.

It should be noted that if a person's BAC is.08% or above, 49 states will consider them to be driving while intoxicated. Only in Utah is a.05% blood alcohol level considered legal for a DUI.

Is a Breathalyzer and Alcohol Detection Generally Accurate After 24 Hours?

Yes, it is. Up to 24 hours after a person's last drink, a breath test may still show alcohol in their system.

However, everyone metabolizes alcohol differently. Therefore, it is possible that a breathalyzer won't detect alcohol after 12 hours, for example, if a person can metabolize alcohol very quickly. However, if their body has a slow metabolism, the 24-hour rule can still be applicable.

The rate at which a person's body metabolizes alcohol depends on a number of factors. A few of these are:

  • Weight/body fat percentage

  • Height

  • Stress levels

  • Rate of alcohol consumption

  • Age

  • Gender

Referring to the final two factors, as a person ages, their body will probably metabolize alcohol slower. Additionally, men often have a faster rate of alcohol metabolism than women.

Regarding various tests and rates of alcohol detection:

  • Alcohol can be detected in a person's blood up to 12 hours after their last alcoholic beverage.

  • A urine test can detect alcohol for up to five days after a person’s last alcoholic beverage.

  • Hair follicle tests can detect a person's blood alcohol concentration for up to 90 days after alcohol consumption.

How Long Does Alcohol Stay on Your Breath?

The smell of alcohol can linger on a person's breath for between 12 to 24 hours after consuming their last drink.

One problem with this is that a police officer might still believe a person is impaired and drunk driving after they have stopped drinking alcohol.

A police officer usually won't arrest a driver for DUI or DWI based on just the smell of alcohol on their breath. However, it can lead the police to subject the driver to more testing and uncomfortable questioning.

How Long Does Alcohol Stay in Your System?

Even after it has been digested, alcohol can still be found in the body and be detected. A common misconception is that if there is no measurable BAC, the person's body is alcohol-free. The blood is constantly circulating and being filtered throughout the body, thus, measuring BAC strictly measures the percentage of alcohol in the blood.

As a result, alcohol is only detectable in the blood for a short period of time after the last drink. There are many ways to measure BAC, including breathalyzers and urine samples. While some of these tests are more accurate than others, they can all detect BAC.

In contrast to the traditional breathalyzer or sweat test, other breath alcohol testing can be effective for much longer. Alcohol consumption results in a 20% initial absorption through the stomach lining, followed by an 80% transfer to the small intestine and dispersion to the bloodstream.

The amount of alcohol that is still present in the body after this is between 2% and 8%. This alcohol has metabolites left behind from incomplete alcohol absorption. The remaining alcohol is removed from the body through urine, sweat, and saliva. There are certain ways to flush alcohol out of the body as well.

Since science has progressed, many tests can now identify these metabolites with variable sensitivity. The most sophisticated of them can tell if someone has consumed alcohol even up to 90 days afterward.

Testing Method for Blood Alcohol Content

There are many test methods that can detect alcohol metabolites and BAC for different periods of time after the body absorbs alcohol. These techniques consist of:

Blood: Alcohol content can still be detected several hours after the last drink. BAC (blood alcohol concentration) is reduced very quickly, and alcohol is not detectable after a short period compared to other testing methods because of the continuous circulation and filtering of the blood.

Essentially, the detection window is smaller, and there are other ways of testing. Blood alcohol tests, even post-mortem, are not always accurate due to possible fermentation and infection.

Breath: Can a breathalyzer detect alcohol? Yes, this is the most common device used by law enforcement and other organizations to detect alcohol usage.

Such breathalyzer tests can detect alcohol poisoning in a person's system for up to 24 hours after ingestion because there is some residual alcohol left in the body that hasn't been fully metabolized. The amount of time that alcohol stays detectable on the breath depends on the quantity of alcohol consumed and the person's system.

Saliva: To detect alcohol consumption, some tests call for a swab of the inner cheek. These tests work well for detecting alcohol intake between 10 and 24 hours after the last drink.

Urine: Tests that analyze urine are available in a wide range of sensitivities to alcohol metabolites. Alcohol consumption that occurred within the previous 12 to 48 hours can be detected using a urine test, which is both less sophisticated and more common.

Within three to four days, more advanced urine analysis tests can identify consumption, as it takes a while for the body to metabolize alcohol.

Hair strands: Testing hair strands is the most advanced and accurate way to detect alcohol use, and it can do so for up to three months.

Due to the cost, this kind of test isn't very popular, but it does have its benefits, such as in cases of parole violations, sensitive employment, and other situations where being fully alcohol-free is necessary.

What Happens to Your Body After Three Weeks of No Alcohol?

After abstaining from alcohol for three weeks, a drinker will start to experience huge benefits. Their blood pressure usually starts to fall as liver function begins to return to normal. Many people also comment on their skin looking healthier because alcohol's dehydrating effects are no longer an issue.

Can You Alter the Results of an Alcohol Test?

Can You Alter the Results of an Alcohol Test?

There is a difference between a test that only checks to see if a person had alcohol in their system and one that examines the amount of alcohol in their system. If BAC (blood alcohol concentration) tests aren't performed correctly, they can be unreliable, and many people try to alter the results by contaminating or delaying the test.

Although people still attempt to cheat on tests that look for biological signs of alcohol use, they are still more reliable. As an example, some people try to get someone else to give them a urine sample.

When an alcohol test is necessary, the testing institution, company, or law enforcement agency usually has a protocol in place to prevent incidents like this from ever happening.

There are many tips and myths for beating a breathalyzer, but most are untrue. While mouthwash and mints may help mask the smell, they have no real effect on blood alcohol levels.

How Long After Drinking Can You Pass a Breathalyzer Test?

A person's maximum level of intoxication after one drink is approximately 0.02%. Within one hour, their alcohol level would be about zero.

On the other hand, if a person had a blood alcohol level of 0.20%, which is double the legal limit for drunk driving in most jurisdictions, it would take over 13 hours for their alcohol level to reach zero after they stopped drinking.

If a person has been charged with a DUI, they can contact the top-rated DWI lawyers at Sparks Law Firm for help.

Contact Sparks Law Firm Today

Several factors affect how long alcohol can stay in a person's bloodstream. Safety and moderation are the key factors. Individuals should refrain from consuming too much alcohol. An alcohol use disorder can enhance depression and other symptoms.

If a person is drinking away from home, they should make sure that they have a ride scheduled. It is never safe to drive while intoxicated, even if the driver is under the legal limit.


bottom of page