Most DUI cases are based on a breath alcohol test result, a blood alcohol test result, or both. Many people don’t understand how unreliable these tests can be for predicting whether a person was impaired for purposes of driving at the time he or she drove. Many people also believe that a drunk driving conviction is inevitable when the state’s chemical test result shows a BAC over 0.08 percent, but this isn’t necessarily the case.
The Purpose of Blood and Breath Tests
Chemical testing is used to predict the impairment level of a driver at a point earlier in time, usually by employing a back calculating technique known as reverse extrapolation. Prosecutors typically assume, allege, and argue that a driver was sobering up (BAC number going down) in the time between driving and testing. This is among the many reasons people charged with DUI must have a skilled Orange County blood and breath tests attorney on their side to avoid being wrongfully convicted.
About Breath Tests and Blood Tests
A breath test is generally administered through a device commonly referred to as a breathalyzer, a piece of equipment which analyzes a driver’s breath sample to estimate the operator’s blood alcohol level. The most commonly used device in Orange County is the Intoximeters Inc. Alco-Sensor IV. The Orange County Crime Lab will phase in the newer model of the same instrument, the Alco-Sensor VXL, in 2014. The new device features a policeman friendly pistol grip and slightly improved electronics. Breath tests are commonly considered to be much less reliable than blood tests. This is because there are a number of issues which arise that can affect the results of the test, and an experienced Orange County blood and breath tests attorney can bring these into question to challenge the results of the breath test.
For example, a breathalyzer must be regularly maintained and calibrated according to state standards as set forth in the California Code of Regulations. If the machine has not been routinely calibrated as directed by law, a DUI defense attorney may be able to use this information to the advantage of the person being charged with drunk driving.
The biggest problem with breath testing is that is does not actually measure a blood alcohol level. The known physiological differences in lung air alcohol concentration as it relates to blood alcohol levels varies widely across the population, but breath testing devices are set to calculate an estimated blood alcohol level based on a fixed ratio of 2100:1. This ratio was adopted by the California legislature as a best guess for average human partition ratios and now supports criminal convictions on a daily basis.
A blood test is conducted by drawing at least 20 cc’s of blood into a vial that contains a pre-mixed preservative and anti-coagulant compound, refrigerating the sample, and eventually processing it using a headspace gas chromatography technique. Although these tests are more accurate and precise than breath tests, they too have their faults. Blood samples may be improperly drawn, preserved, handled, stored, or analyzed. Local authorities have openly admitted that analysis of blood alcohol concentrations were reported falsely high for a number of months before a calibration error was discovered.
Hire An Orange County Blood and Breath Tests Attorney
The attorneys of The Law Offices of Todd Landgren today are well versed in blood and breath alcohol testing in Orange County and stay abreast of every recent development that could prevent the wrongful prosecution of DUI defendants in Orange County. For the most locally knowledgeable and skilled Orange County Blood and Breath Tests attorney possible, contact The Law Offices of Todd Landgren.