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Conway Criminal Law Blog

Should I Take a Breath Test or a Blood Test?

If a police officer pulls you over for drunk driving, the officer may administer a blood alcohol test. Each test is administered differently, and in South Carolina, a motorist is usually asked to take a breath test if an officer suspects alcohol use. In this article, our Conway DUI lawyer would like to provide an overview of breathalyzers versus blood tests in South Carolina.

South Carolina DUI Laws

In South Carolina, it is illegal to drive if you have a blood alcohol concentration (BAC) of 0.08% or higher. If you are driving in South Carolina, you have already agreed to take a blood, breath, or urine test to determine the presence of alcohol in your system. This is known as the state’s Implied Consent Law.

Under South Carolina law, a person must first be offered a breathalyzer test, which must be administered within two hours of your arrest. If you are unable to take the test due to an injured mouth, you are unconscious, or if your sample is considered unacceptable by a medical professional, a police officer may request a blood sample.

However, if you refuse to provide a sample OR if you provide a sample and register a BAC of greater than 0.15%, your license will be suspended. 

What is a Breathalyzer Test?

A breathalyzer is an electronic device that measures the amount of alcohol in a person’s blood. When someone breathes into a breathalyzer, the machine will provide a written report with your BAC. If your BAC is at 0.08%, a judge will infer that you were operating a vehicle under the influence of alcohol. If you register greater than a 0.10 but less than a 0.15% the potential penalties increase. If you register greater than 0.15% the penalties are substantially increased.

Breathalyzer Test versus Blood Test Readings

Breathalyzer Tests

A breathalyzer is estimated to be correct 40% of the time. That is because these devices are known to be poorly calibrated. The device needs to be calibrated periodically, and if it is not regularly maintained, then you are bound to get an inaccurate reading.

Besides miscalibration, certain medical issues are known to cause the machine to have a false positive reading. For example, anyone diagnosed with diabetes, kidney, or liver disease may fail a breathalyzer when they are, in fact, sober.

For diabetes sufferers, this is caused by high acetone levels in the blood. For those who suffer from kidney or liver disease, it is caused by excessive amounts of ammonia in the blood. So, if you have a medical condition, it is probably best to opt for a blood test.

However, the unreliability of a breathalyzer test may make it a more favorable option. A DUI lawyer may be able to collect indirect evidence to prove that you were not impaired.

Blood Tests

The same does not hold true for blood chemistry tests, which have an accuracy rate of well over 90%.

While blood tests are more intrusive, if you were driving sober, it would be in your best interest to take the blood test and put the matter to rest once and for all.

Arrested for DUI? Speak with a Conway DUI Lawyer Today

If given the choice between a blood test or a breathalyzer, the best option will depend on your situation. Our Conway DUI lawyer has helped defend many clients against drunk driving charges and is ready to work for you. Contact the office today online or by calling 843-488-4321 to schedule your consultation.