What is Blood Alcohol Concentration (BAC)?
BAC is the measure of the amount of alcohol in someone's bloodstream. Blood alcohol concentration (or "content") is expressed as a percentage – for instance .08%. The higher the number, the more alcohol there is in a person's bloodstream.
This is typically the most important measurement to any Idaho DUI case. Although a BAC above .08 is not required for a DUI conviction - in fact you can be convicted of DUI without any BAC measurement (see Non Per Se DUI) - a BAC measurement can be difference between a conviction and an acquittal. Take a look at some of the blog articles I have written on the subject.
There are frequent problems with the tests used in measuring a person's BAC. An experienced DUI attorney may be able to challenge the results of these tests.
Several factors can affect a party's BAC levels when drinking. Some of the more popular include:
- age – as age increases, the intoxicating effects of alcohol become more pronounced.
- food - consumption of food can effect BAC measurements
- gender – women will generally reach a higher blood alcohol concentration if they drink at a similar rate to a male counterpart.
- rate of consumption – the faster a person drinks alcohol means the quicker his/her BAC will rise.
- weight – an increase in weight usually means that a person can drink more without a drastic rise in BAC levels.
- stress – this can actually lower the rate of alcohol absorption into a person's body. This means a lower BAC. Thus, stress can actually have a lowering effect on a drinker's blood alcohol concentration level.
The Breathalyzer Test
If you are pulled over and suspected of Driving Under the Influence (DUI) in Idaho, the most common method used to determine BAC is the breath test.
Breath tests are considered reliable enough to stand up in court, but that doesn't mean they don't come with a margin for error. If drivers are tested and the results are close to the legal limit, DUI attorneys can often argue that the machine gave an incorrect reading, and therefore help your case.
Breath test machines must be properly maintained with regular accuracy checks and calibration. Failure to do so will result in the breath test machines giving inaccurate test results. Proper records must be kept if the test results are to be used against you.
Portable vs Stationary Breath Machine
There are many differences between the types of machines used to determine BAC. Each of these has their strengths and weaknesses. A skilled DUI attorney will be able to point out the flaws of the machine used in your case for determining BAC.
The Blood Test
Blood tests are not the most frequently-used tests due to their complex processing requirements, but they are known to be the most accurate in determining the exact amount of drugs and/or alcohol in a driver's system.
Proper blood draw procedures must be followed if a blood test is given and the blood vial must be handled properly during the period prior to the testing or the BAC result will not be accurate. Blood is often shipped from location to location, leaving a lot of room for mishandling and contamination. Proper handling procedures, documenting chain of custody and preventing contamination, must be followed if the test results are to be used against you.
Presently, drug testing labs do not have the ability to identify drugs in an individual's system accurately enough to determine whether or not an individual was driving while actually under the influence. This means that DUI charges involving drugs can often be made more on speculation, rather than hard facts and evidence.
Medication or Drug DUI - Blood Testing
Unlike DUI cases involving alcohol, there is no BAC limit that allows officers to gauge a person's impairment. In fact, even if a blood test indicates a high level of a certain prescription drug is in the person's system, this does not necessarily mean that the person was impaired while driving. To begin with, different drugs affect the human body differently, so an individual's level of impairment depends on:
- The type of drug they have taken.
- The quantity they have taken.
- The time they took it.
- The tolerance level they have to that drug.
Of course the blood test is going to test positive for the prescription drug you are properly prescribed and take at your doctor's direction, it would be odd if you didn't test positive for this prescription drug. However, just because you test positive does not mean you are impaired by the prescription medication.
Additionally, some drugs are detectable in blood tests long after the effects of the drug have worn off. The classic example of this is marijuana, which remains in the body for up to a month since the last use. Even if you test positive for a prescription medication or drug, a positive test does not prove you were impaired at the time you were driving the motor vehicle.
I see people plead guilty to DUI all the time even though they do not believe they are guilty. They assume that they can not win because their blood test came back positive for a prescription medication. Do not fall into this trap!
A skillful DUI defense attorney will know how to cast reasonable doubt on the accuracy of the blood or breath test results. Call me today for a free consultation.