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Rules For Obtaining A Blood Sample After A Dui Arrest

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There is much confusion over the rules for obtaining a blood sample after a DUI arrest. Many people are unclear of the laws regarding DUI cases and what’s permitted in court. Do you have to submit to a blood test? What can affect a blood alcohol test? This blog will answer these questions and more. 

Here, you will learn what your rights are while gaining a comprehensive understanding of the DUI blood test. If you have already submitted to a blood test or you’re facing a DUI case, this article will offer guidance and direction as to how to proceed.

What is a DUI Blood Test?

The term “DUI” is an acronym for Driving Under the Influence. Moreover, DUI means operating a motor vehicle while intoxicated with drugs or alcohol. Every state has its own DUI law that dictates it is illegal to drive while intoxicated, whether under the influence of alcohol, marijuana, prescription medication, or illicit drugs. 

What’s more, some states have laws in place that differentiate between the various possible DUIs, such as one involving alcohol and one involving an over-the-counter medication like cough syrup. And it’s because there are so many possible scenarios involving DUIs that blood tests exist.

Blood tests help determine the blood alcohol content (BAC) in persons charged with DUI. If you are pulled over, and the police officer determines that you are intoxicated, blood testing can be ordered. 

But unlike breathalyzers, blood tests are almost never performed at the scene of the arrest. Unless there is a unique situation where a qualified medical practitioner is present at the scene and has the necessary equipment to legally do so, all blood tests take place in a medical facility.

Moreover, blood alcohol testing in hospitals ensures that proper laws regarding chemical testing are followed. Some states have strict regulations in place that dictate who can take a blood sample and test alcohol levels, as well as the manner in which the samples are analyzed and transported.

It’s rare that police officers are trained and equipped to administer blood tests. And even you are pulled over for DUI by an officer that can perform blood draws, your state’s laws may prohibit them from doing so at the scene.

If you discover that someone took a blood sample from you who wasn’t qualified to do so, you can legally challenge the results of the blood test.

What Can Affect a Blood Alcohol Test?

Blood alcohol tests are used to determine the blood-alcohol concentration (BAC) of a driver suspected of driving while intoxicated. BAC is defined as the amount, by weight, of ethanol in 100 milliliters of blood or 210 liters of breath. 

There are a number of factors that can affect the validity of this test. Some things that may cause an inaccurate reading include time from alcohol consumption, having diabetes, taking certain medications, or eating food right before the test. 


Your body absorbs alcohol the moment you consume it, and it does so quite efficiently. However, it can take as much as 60 minutes for your blood alcohol concentration to reach its peak. Therefore, it is very likely that a blood alcohol test conducted 30 minutes before or 30 minutes after the peak 60-minute mark would yield very different results.


This is a very significant factor that can radically change blood alcohol levels. For instance, some medicines can cause a person’s body to respond in a way that limits the effects of alcohol, while other medications can actually make the effects worse.


The more food you have in your body, the longer it takes you to absorb alcohol into your blood. Therefore, if you and a friend have been drinking the same amount of alcohol, but you have an empty stomach, it’s likely that testing you both would should you to have a higher blood alcohol level.

What is the Legal Limit for Blood Alcohol Content?

In every state, the legal limit for BAC is 0.08%. However, the limits vary when it comes to increased penalties. For example, the California BAC limit is 0.08%, with penalties increased for anyone caught driving with a blood alcohol content of 0.15% or higher.

If you are facing DUI charges, it is important to secure the legal counsel of a qualified DUI attorney. Your lawyer will ensure your rights are not violated.

For your blood test to count as evidence in court, prosecutors must follow what’s called the “chain of custody.” This means that they must establish the following to the court in order for the blood test to be accepted as evidence:

  • Who performed the blood draw
  • Whether they were qualified
  • Where it was taken
  • How it was taken
  • Who analyzed it
  • Their qualifications
  • Protocols in place to ensure your sample was constantly accounted for
  • Protocols in place to ensure testing equipment was constantly accounted for
  • The use of a common testing method
  • Proper storage and transport of sample

In addition, there is special documentation in place that must be signed and dated every time a blood sample changes hands. In DUI defenses, attorneys carefully research and review the above requirements and make sure the proper paperwork was used throughout your testing.

If anything was ignored, overlooked, or protocol wasn’t followed correctly, your attorney will fight to have your sample disqualified as evidence.

Penalties for Refusal of a Chemical Test

Each state has its own implied consent law, which can result in penalties for refusing to take a chemical  test- whether a breath or  blood test- when authorities have a basis for believing you are operating a motor vehicle while under the influence. What type of penalties you might face depends on the state in which you are pulled over. However, while you can face additional penalties for refusing to take a blood test and the refusal can be used as evidence of guilt at trial, you cannot face a separate criminal charge for refusal of a blood test.

Blood Test Administration: How It Works

If you do anything to purposefully delay the test, the police may deem you a refusal. With that said, you can request that a different type of test be administered to you, such as a breath test if it is available.

Just be aware that if alternative tests aren’t available, you must agree to the blood test. Upon administration, a qualified person will use a syringe to draw blood from a vein. That sample is stored in a vial that is then sent off for analysis.

If you are concerned about the way your blood test was handled or you want to ensure that you are fairly represented, contact a trusted DUI attorney today.

The post Rules for Obtaining a Blood Sample After a DUI Arrest appeared first on Law Offices of Taylor and Taylor - DUI Central.

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