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San Diego DUI Breath and Blood Tests

If you were recently arrested for Driving Under the Influence (DUI), it is almost certain that you were issued either a blood or breath test.  Many people assume that just because they failed their DUI test there is nothing they can do to fight the charges against them.  However, there are many instances in which the results of your test could have been inaccurate.  Furthermore, there are a number of scenarios in which even if the results are accurate they should not be admissible.  For this reason, it is extremely important that you contact an attorney right away. Our lawyers at the San Diego DUI Attorney have years of experience in challenging the results of DUI Tests. We will aggressively argue on your behalf to ensure you receive the best defense available.  If after reading this article, if you think we can be of service to you, contact our office at 619-535-7150 for a FREE DUI consultation.

DUI Breath Test

A breath test analysis, administered by a law enforcement officer following a DUI traffic stop, provides an indirect value of your blood alcohol concentration (BAC). This test measures the level of alcohol in proportion to exhaled air, not the level of alcohol in the blood stream and errors can happen in the testing process.

Some factors that can affect the results when testing for BAC with a breath analyzer include:

  • Body temperature or respiration rate of the person being tested.
  • Amount of time that has passed between the traffic stop and testing.
  • Presence of alcohol-containing substances in the mouth (e.g. mouthwash).
  • Presence of stomach fluid (bile) due to vomiting or regurgitation.
  • Malfunction or poor calibration of the breath analyzer.
  • Improper application of the breath analyzer during testing.
  • The analysis of your breath involves a mathematical ratio, which is an estimate of the “average” person. Thus, it can be seen as an inaccurate analysis of your BAC. In addition, values may fluctuate based upon any of the factors listed above, calling the results into question.

Because breath analyzers have been found to be inaccurate, police officers may instruct you to take the test multiple times in order to achieve consistent results. If you fail to comply by providing these repetitive samples, your driver’s license can be suspended for a period of one year.

The defense lawyers at San Diego DUI Attorney are very experienced in revealing errors of the breath analysis process and can help to make sure your rights are protected when charged with driving under the influence.

DUI Test

DUI Blood Test

A blood test is the most accurate test available to measure an individual’s blood alcohol concentration or the presence of drugs in an individual’s system following a DUI arrest. As is the case with the breath analysis, errors may occur when collecting, testing, and analyzing blood samples. For example, sometimes blood samples are not properly preserved or they may not be tested in a timely manner. In such cases, the samples may begin to decompose or coagulate and this can lead to false readings. Improper record keeping, contamination of a sample, or failure to follow proper procedures at the testing laboratories are all reasons that blood alcohol test results could be compromised.

Blood test results are not infallible. Our experienced attorneys at San Diego DUI Attorney can determine when questionable or faulty processes have affected the credibility of your test results. Call San Diego DUI Attorney today to schedule a FREE initial consultation to review your case. We are dedicated criminal defense lawyers and will help you when facing charges for driving under the influence in San Diego County.

Blood Test vs. Breath Test

Another one of the more common questions DUI lawyers are asked is: “Should I choose to take a breath test or a blood test?” 

Unfortunately, there is no definitive answer.  Both have their pros and cons, and it’s extremely difficult to know ahead of time which will be more beneficial. 

It is generally agreed upon that blood testing is more accurate.  Obviously, the test’s accuracy can be a good or a bad thing depending on what your BAC was.  However, while the blood test is generally more accurate, it’s also easier to cross-check.  Because a blood test will use a blood sample, which is preserved, your defense attorney can have an independent lab run a cross-check to ensure the results were accurate. 

On the other hand, when you take a breath test, no breath sample is preserved.  As such, there is no way to run an independent test to verify the results of the breath test.  Even so, breath tests are thought of to be far less reliable than blood tests and render a much higher percentage of false-positive results.   

Refusing a Breath Test

One of the most common questions DUI Attorneys are asked is: “am I allowed to refuse a breath test?”  The answer really depends on when the breath test is being administered and whether you are willing to deal with the consequences of refusing.

The first thing to understand, is that most DUI incidents involve two distinct breath tests.  The first is called the “preliminary alcohol screening (“PAS”)” test.  This is the test given to the driver roadside, and before the driver is arrested.  If the driver is ultimately arrested, they will then be given a second test known as the “evidentiary test”.  This second test is issued back at the police station. 

Technically, in most cases, you can refuse to submit to either test.  However, there can be consequences for refusing each, and some can be quite severe.

Refusing the Preliminary Alcohol Screening (PAS) Test

In most DUI incidents, you will be offered a PAS test after you are pulled over by the police.  This preliminary test you are actually permitted to refuse, unless you fall into one of the following categories:

  • If you are on probation for driving under the influence at the time the test is offered; or
  • If you are under 21 years of age at the time the test is offered.

Unless you fall into one of those two categories, you can refuse a PAS test without any penalty.  This is because the purpose of the PAS test is to assist the officer in determining whether they have sufficient cause to arrest you (Note however, there are signs, other than your BAC, that can give the officer sufficient cause to find you intoxicated, and place you under arrest).

Refusing the Evidentiary Test

Refusing the post-arrest evidentiary test will lead to consequences.  This is true even if you previously took the PAS test.  Typically, in a DUI case you will be given the choice of submitting to either a breath or blood test.  Refusal to submit to the evidentiary test can lead to the following consequences:

  • An enhanced jail sentence of up to two (2) days if you are later convicted for DUI; and/or
  • A driver’s license suspension for a minimum of one (1) year.

California Code of Regulations – Title 17

Title 17 regulates the manner in which breath and blood samples must be collected and stored.  Failure to adhere to the Title 17 procedures can result in inaccurate BAC scores, and can render a blood or breath test inadmissible. 

Title 17 - Breath Test Rules

The most important, Title 17 rules regarding the administration of breath tests are as follows:

  • The officer administering the breath test must be properly trained;
  • The DUI Breathalyzer must be properly maintained, tested, and calibrated;
  • The officer administering the breath test must observe the defendant continuously and for 15 minutes prior to administering the test;
    • During these 15 minutes, the defendant may not smoke, drink, eat, or vomit.
  • The officer must collect two (2) samples that are not more than .02g/ml apart from each other.

Title 17 – Blood Test Rules

Just as with breath tests, there are several guidelines that must be followed with regard to the collection and storage of blood tests.  These include the following:

  • The technician who take the blood sample must be properly trained;
  • The blood sample must be stored properly;
  • The instruments used for calculating the BAC must be properly calibrated;
  • There must be a record of everyone who handles the blood sample;
  • The location on your body where the blood is drawn must be sterilized with something other than an alcohol based product.

As noted above, blood tests are generally more accurate than breath tests.  Further, it is presumed by law that that blood samples were obtained and stored in compliance with Title 17.  As such, the burden is on the defendant to prove any inaccuracies that might exist. 

How a Breath Test Works

It may come as a surprise, that a DUI breath test does not directly measure your blood alcohol.  This is one of the reasons why blood tests are thought to be more reliable.  Breath tests, as the name suggests, actually measures the amount of alcohol in your breath.  They then use a mathematical conversion to calculate the amount of alcohol in your blood.

Common Breath Test Errors

As mentioned, breath tests are subject to a number of errors and inaccuracies.  Errors are most commonly the result of either improper administration or faulty equipment.

Faulty Equipment

Title 17 contains the rules as to how breath test equipment should be tested and calibrated:

  • The breath test device must be of the type approved by the state of California;
  • Detailed records of the device’s maintenance must be kept; and
  • The device must be calibrated every 150 uses, or 10 days (whichever is first to occur).

Improper Administration

Common administration errors include:

  • Failing to properly attach the mouthpiece;
  • Failing to check that the driver’s mouth is empty prior to administering the test;
  • Not properly recording the time of the administration;
  • Not observing the driver continuously and for 15 minutes before administering the test.

Other Factors That Can Lead to Inaccurate Results

  • Medical Conditions;
    • Gastrointestinal reflux disease, acid reflux, and heartburn can all lead to inaccurate results;
  • Diet;
    • Low Carb diets, and High Protein diets can also lead to inaccurate results;

Refusing a Blood Test

Refusing a blood test is very similar to refusing a post-arrest evidentiary breath test.  Essentially if you refuse, there will be penalties.  Further, with blood tests, the police will in some case obtain a warrant to force the blood draw.

Blood Test Refusal – No Warrant

When you accept your California driver’s license, you effectively give your consent to submit to a post-arrest DUI test (blood or breath).  Therefore, just as when you refuse an evidentiary breath test, if you refuse a blood test, you will be subject to the following penalties:

  • An enhanced jail sentence of up to two (2) days if you are later convicted for DUI; and/or
  • A driver’s license suspension for a minimum of one (1) year.

Blood Test Refusal – With Warrant

In some cases, the officer who arrests you will seek to obtain a warrant to force a blood draw.  If a warrant is issued, you no longer can refuse the test and you can actually even be physically restrained and forced to submit to the test.  With a warrant, you can also be issued a forced test if you are unconscious.    

Independent Blood Test

As noted above, one of the main advantages to choosing a blood test is that you can have your sample re-tested at an independent lab.  The independent lab may discover that the original test was inaccurate for a number of reasons such as:

  • The sample or blood vial was mishandled;
  • The sample had an inadequate amount of preservative;
  • The sample was contaminated; or
  • The sample was improperly stored/refrigerated.

If you have been charged with Driving Under the Influence, contact the San Diego DUI Attorney today for your FREE DUI Consultation.  Our Chief Trial Attorney, Vincent Ross, has nearly three decades of experience, and has handled thousands of DUI cases.  Our defense team has the resources to treat your case with the individualized attention it requires.

Call us today at 619-535-7150.

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