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Blood Tests

The driver’s blood-alcohol level is the best proof of illegal intoxication. Because the result can be used against the driver in a court of law, he can refuse to be tested based on the right against self-incrimination. However, most states have enacted laws that permit the suspension or revocation of the driver’s license if the test is refused under their "implied consent" laws.

Do I have to submit to a blood test?

Yes. Driving is a privilege not a right, and if you refuse, your license will be automatically suspended.

TIP: If you are not a licensed driver in the state where you were stopped, you may be able to refuse the blood test without losing your license. Because you have not agreed to the implied consent laws of that state, the laws cannot be used against you.

Is a blood test required to show that I was driving under the influence or while intoxicated?

No. A blood test is one of several ways to prove DUI. The arresting officer can also testify to circumstance and actions that indicate you were driving under the influence (e.g., weaving, no lights on, slow and irregular speeds).

SIDEBAR: Depending on the state, the law may require a certain level of intoxication (e.g., .08 percent) either at the time of the test or the time of the offense. The distinction is important because alcohol takes time to be absorbed, and in a state where the driver must be intoxicated when driving, the defense can argue the alcohol had not yet absorbed to the legal level.

My blood alcohol test showed alcohol levels less than the legal limit. Why am I still being charged with a DUI?

A chemical test is not required to prove the offense. If there is evidence that you were driving while impaired (e.g., weaving, no lights on or slow and irregular speeds), you can be convicted.

I tested above the legal limit on the blood alcohol test but I believe I was not impaired. Can I offer evidence that I was operating my vehicle without impairment?

No. Since you tested above the legal limit, you can only contest the accuracy of the test. The test established your impairment and it is no longer a question.

What is "implied consent"?

Implied consent laws mean that by obtaining a license to drive on the state’s roads, you have consented to testing if asked and if you do not consent, your license is suspended or revoked.

I know I have to consent to a blood test but can I still refuse a urine or breath test?

No. Urine and breath tests are not as reliable as blood tests, but they are still chemical tests you must consent to or have your license suspended.

TIP: If you are given a urine or breath test instead of a blood test, you have an excellent chance of contesting their accuracy.

What is the effect of blood testing results?

If the results of a blood test show an alcohol concentration above the legal limit, the offense of driving while intoxicated or under the influence has been conclusively established. In other words, in a trial, the jury would be required to find you guilty of a DUI once the prosecutor put the blood test into evidence.

What is the procedure for blood testing?

All states have strict guidelines for blood testing. For example, in some states only a physician or authorized medical personnel can draw blood, and failure to follow the procedures may invalidate the test.

TIP: If the testing procedures are not followed, object to the evidence at trial as lacking in foundation. The judge should refuse to admit it.

What is "infrared breath testing"?

Although the Breathalyzer has been the long-favored test for blood alcohol concentration, new technology is being utilized by law enforcement agencies. Infrared or "IR" testing is more sophisticated and courts have found the test results reliable.

TIP: Some medical conditions, such as diabetes, may give an erroneous intoxication result in a Breathalyzer test.

TIP: Testing equipment must be in working order and operated by a knowledgeable, trained person. If the prosecutor is unable to prove the equipment and testing was reliable, argue that the test is invalid and should not be admitted into evidence. Often a certification is required for the operator of breath-testing equipment. If the certificate has expired, the test results should be inadmissible.

What kinds of questions should I ask the operator of the blood test equipment?

If you are handling the citation yourself, ask the operator:

  • How old is the equipment?
  • When was it last inspected and calibrated?
  • Where is it stored and how many people have access to it?
  • How many people are designated operators?
  • Are operators required to be trained and/or certified?
  • Were you trained on the equipment? By who and when?
  • How many hours of training did you receive and when was the last training session?
  • Do you know if all the operators are properly trained and certified?