Police use three methods to ascertain blood alcohol concentration (BAC): blood tests, breath tests and urine tests. In California, blood and breath tests are most common. But none of these tests are reliable in all cases.
If you’re sure you were not over the .08% BAC limit, it’s for one of two reasons:
- You were drinking, but you’re sure you weren’t drunk.
- You did not drink at all, and it’s impossible that you were drunk.
We’ll look at each of these in detail.
If You Were Drinking
It’s possible for some individuals to have one to two drinks and still be under the legal limit. It’s also possible to have some alcohol still in the system from hours ago, or the night before. Generally, if you felt “buzzed” or “tipsy” you were probably over the legal limit. If not, it’s possible your BAC was below .08%.
Here are some reasons the test may have returned a higher result:
- Testing error. Chemical tests aren’t perfect. They can give false results. In a breath test, this usually means the device wasn’t calibrated properly. Or it may mean this particular device has a history of skewing high. In a blood test, it can mean the sample was not properly handled, stored, or tested. If any of these factors is involved, a DUI lawyer can find evidence of it and potentially have the test results dismissed.
- Mouth alcohol. The alcohol that a breath test detects is from air deep in the lungs—not the “breath” in the mouth. But if there is a source of alcohol in the mouth, it can throw off the result. This can come from breath spray or mouth wash, from burping or acid reflux, or could be trapped in dentures and braces. See our complete mouth alcohol guide for details.
- Rising BAC. It’s possible that you were under the .08% limit while you were driving, but your BAC had gone up by the time you were tested. This happens because it takes time for the body to absorb alcohol from the stomach. The most common reason for rising alcohol is that the police waited too long to test you.
- Normal variation. Tests have a margin of error. If your results were close to the limit—.08 to .10, for example—you may have actually been legal. Test results like these can often lead to getting a charge reduced to something lesser, or even dismissed.
If You Didn’t Drink at All
Some drivers are shocked by the allegation of DUI because they had no alcohol whatsoever. If this is you, there are several reasons you would still get a BAC result of .08% or more:
- You took medicine that contains alcohol, such as Listerine
- You used mouth wash or breath spray that contained alcohol
- You have diabetes
- You eat a low-carb, high protein diet
No matter what the reason, if you believe your BAC result was wrong, you need to speak to a lawyer. We can match you with a top Los Angeles DUI lawyer who has the right experience for your case—and get you a FREE consultation. Just fill out the form to your right and get your free consultation today.