Blood Alcohol Testing

Blood alcohol testing allows law enforcement to determine how much ethyl alcohol is in a person’s bloodstream.  The results are given in percentage in milligrams.  If someone has a blood alcohol test result of 0.08% or higher, he or she is considered impaired according to California DUI law.  If a person’s blood alcohol test result is slightly below 0.08%, he or she still might be considered under the influence of alcohol if he or she displays certain behavior.

It is important to remember that the blood alcohol test is intended to determine the driver’s blood alcohol concentration at the time the he or she was operating a motor vehicle, and not after the fact. There can be a significant difference between a driver’s BAC at the time of driving and the time the chemical test is administered. California law requires evidential blood tests to be conducted in compliance with California Code of Regulations.  Title 17 is the governing section of the California Code of Regulations applicable to blood alcohol testing. 

There are three types of tests that law enforcement uses to determine a person’s blood alcohol level.  Blood alcohol can be measured by a person’s breath, blood, or urine.  Certain factors such as gender, amount of alcohol consumed, weight, type of alcohol consumed, and food consumption can significantly impact the results of a blood alcohol test.

Breath Alcohol Testing - During a breath alcohol test, the person blows into a machine such as an Intoxilyzer 5000 manufactured by CMI.  A person’s breath alcohol concentration is indirectly correlated to a person's blood alcohol level.  However, the formula chosen by the California State Legislature to establish the relationship between breath alcohol results and blood alcohol level is arbitrary and does not apply to each individual.  The American Medical Association has reported that a person may be impaired with a BAC of 0.05%.  Most states, including California, have adopted 0.08% as the standard.  This means there is 0.08 grams of alcohol present per 210 liters of breath. 

Blood Alcohol Testing - Through a blood alcohol test, a person’s blood alcohol content can be directly determined.  Blood testing is the most accurate way to determine a person’s blood alcohol concentration at the time of the chemical test, not necessarily at the time of driving.  During a blood alcohol test, blood is drawn from a person’s arm, and then it is analyzed.  If the blood test reveals the person’s blood alcohol concentration to be 0.08% or greater, that person is considered impaired.  

Often there is a delay in the specialist (phlebotomist) who draws the blood responding to the law enforcement facility to obtain the sample.  This can leave the blood alcohol result open to challenge because the blood alcohol level may have risen since the time of driving.

Urine Alcohol Testing - A urine alcohol test measures a person’s blood alcohol concentration indirectly.  After a urine sample is obtained, it is analyzed, and a ratio of 1.3:1 is used in estimating the alcohol concentration in the urine.  If the urine test reveals that the person’s blood alcohol concentration was 0.08% or greater, he or she is considered impaired.  The problem with urine testing is that unless there was a complete void (emptying) of the bladder prior to obtaining a sample, the results are subject to challenge because urine may remain in the bladder for a prolonged period of time.

San Francisco DUI Attorney

If you have been arrested for DUI in San Francisco, obtaining a qualified attorney is the most important decision you will make.  An experienced and committed DUI defense attorney can protect your legal rights, investigate the circumstances surrounding your arrest, question law enforcement officers and independent witnesses, and inform you of your options, .  A skilled DUI attorney can also provide the resources and aggressive defense you will need to successfully fight your DUI charges.

Robert Tayac has been helping people charged with DUI in San Francisco for over a decade.  He has the education, specialized training, and experience to help you and manage or defend your drunk driving case.  Robert Tayac will also schedule your hearing with the California DMV and represent you at the hearing.  Remember, you only have 10 days to prevent your driver's license from automatically being suspended by the DMV.  If you hire Robert Tayac, you will know that you have retained the services of a knowledgeable and trustworthy DUI defense lawyer and that your case is being properly handled.

Contact the Law Office of Robert Tayac for your free case evaluation!