Why a DWI Blood Test Can Be Inaccurate

In Texas, you are required to submit to a breath or blood test to determine your blood alcohol content (BAC) when you are under arrest for DWI. Unless the suspected DWI caused an accident resulting in injury or death, however, you can decline any such test. This, however, will result in penalties that may include a license suspension, even if you ultimately avoid conviction for DWI.

This makes it risky to choose to refuse a DWI blood test, so you should consult with an attorney for guidance in your specific situation. That said, there are reasons to consider declining a blood test anyway, especially when a false positive could lead to worse consequences.

Are DWI Blood Tests Reliable?

DWI blood tests are often considered to be the most accurate assessment of a driver’s BAC, but they aren’t infallible. Although a blood test can provide a more accurate read of a driver’s sobriety than a field sobriety test or even a breathalyzer test, human error and natural processes can generate false positives that can result in unfair convictions.

Reasons for DWI Blood Test False Positives

When blood is drawn after a suspected DWI, it’s crucial that it’s properly labeled, protected from contamination, and properly stored.

If a sample is improperly labeled, it can get mixed up with another sample. That can have serious consequences if your DWI blood sample is mixed with another defendant’s that has a BAC greater than 0.08%. The same can happen if testing conditions aren’t sterile. Your sample can be contaminated by someone else’s blood, generating a false positive.

Proper storage is also important because blood can ferment. If blood isn’t kept in cold storage, fermentation can cause the BAC in the sample to rise and exceed the legal limit by the time it’s tested.

Arrested for DWI? Call a Lawyer.

If you are arrested for DWI, contact a lawyer as soon as possible. Only an experienced criminal defense attorney can provide the legal support and guidance you need to deal with a DWI blood test. Your attorney can also challenge the results of any blood test you take if there are plausible alternative explanations for why your sample may show a BAC above the legal limit.

Don’t wait – The Law Office of Rene A. Flores PLLC can help. Contact us online now to learn more.

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