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A breath alcohol test is an estimate of your
blood alcohol concentration (BAC). The test measures the amount of alcohol in
the air that you breathe out (exhale).
You can measure your own
breath alcohol level with a simple handheld device. If the device is calibrated
and used according to the manufacturer's directions, it can provide an accurate
estimate of your blood alcohol level. There are different types of devices available. You can get simple devices meant for home use and professional devices like those used by police for suspected drunk drivers.
Within minutes after you drink alcohol, your blood alcohol
concentration starts to rise. Unlike food, alcohol is absorbed directly through
the walls of the stomach, goes into the bloodstream, and travels throughout
your body and to your brain. This allows blood alcohol levels to increase
The amount of alcohol in your blood reaches its highest
level about 60 minutes after you drink. But food in your stomach may
increase the amount of time it takes for the blood alcohol to reach its highest
level. Most of the alcohol is broken down in the
liver. The rest of it is passed out of your body in
urine and your exhaled breath.
You can buy breath alcohol devices
to measure your BAC at many pharmacies or through the Internet.
Many bars and restaurants provide their customers with free
alcohol breath tests using one of these two methods. The devices are also used
to monitor people in an alcohol rehabilitation center or hospital.
The breath alcohol self-test is used to
estimate your blood alcohol concentration (BAC). The results can help you
decide whether it is safe to drive. This estimate of blood alcohol is not
intended to represent your actual driving abilities. Your driving may be
impaired even with a low BAC level, such as below 0.05.
alcohol test offers one piece of information to help you make a safe decision
about drinking and driving. The safest decision is always not to drive if you
have been drinking.
BAC is commonly used by police and other
legal authorities to determine whether a person is legally impaired and should
not drive. A blood alcohol concentration (BAC) 0.08 or greater is
considered legally impaired for adults in the United States. But the legal BAC limit for people under age 18 may be lower, such as 0.02.
To obtain a
breath alcohol reading:
If your test has only the glass tube, blow through the
tube for the amount of time in the instructions. Use one long breath, not
several small breaths. Then look at the colored crystals to get the
The amount of alcohol in your breath is based on the
number of bands that change color and on the intensity of the color
specific instructions that come with the device. With most meters, you:
The results appear as a digital readout in a display
window. It may show a red or green "traffic light" or an estimated blood
alcohol concentration (BAC). After you obtain the first reading,
press the reset button and do a second test.
There is no pain from a breath alcohol
There is no chance for problems from taking this
test. You might feel slightly
lightheaded after taking the test.
A breath alcohol test is an estimate of
your blood alcohol concentration (BAC). The test measures the amount of alcohol
in the air that you breathe out (exhale). Results are ready right away.
To read the glass
tube breath alcohol test, count the number of yellow bands of crystals that
devices have a "traffic light" display.
Some devices display the results as an estimated BAC
No home test is 100% accurate.
The results may not be helpful if you:
blood alcohol level depends on:
A blood alcohol test is more
accurate than a breath alcohol test. To learn more, see the topic
Driving under the
influence of alcohol (DUI) can be deadly. Alcohol is involved in nearly half of
all fatal highway accidents. Even mild intoxication can impair your ability to
drive safely. At 0.06 BAC, your judgment and physical coordination are
impaired. At a BAC of 0.08, your muscle coordination and driving ability are
A person who drinks alcohol and takes
certain medicines, such as
sedatives (tranquilizers), or opioids, may feel more of the
effects of alcohol. Also, a person who uses other drugs, such as marijuana,
will feel the effects of both drugs more than if the drugs were used
Having any amount of
alcohol in the blood can cause poor judgment and slowed reflexes. BAC and the effects of
drinking alcohol vary from person to person and depend upon body weight, the
amount of food eaten while drinking, and each person's ability to tolerate
Relaxation, slight body warmth
Sedation, slowed reaction time
Slurred speech, poor coordination, slowed
Difficulty walking, double vision, nausea,
May pass out, tremors, memory loss, cool
Difficulty breathing, coma, possible
You can buy breath alcohol tests on the Internet,
either directly from the manufacturer or from a company that sells this kind of
product. If you have access to the Internet, you can find this information by
searching for the type of test or the name of the manufacturer.
Other Works Consulted
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
ByHealthwise StaffPrimary Medical ReviewerE. Gregory Thompson, MD - Internal MedicineAdam Husney, MD - Family MedicineMartin J. Gabica, MD - Family MedicineKathleen Romito, MD - Family MedicineSpecialist Medical ReviewerR. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology
Current as ofNovember 10, 2016
Current as of:
November 10, 2016
E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & Kathleen Romito, MD - Family Medicine & R. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology
To learn more about Healthwise, visit Healthwise.org.
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