Can a blood or breath test be wrong for DUI purposes?

On Behalf of | Oct 31, 2023 | DUI |

In the realm of DUI cases, blood tests and breath tests serve as important tools for law enforcement to determine a driver’s blood alcohol concentration. These tests help to uphold road safety and accountability for many individuals who drink to unsafe limits.

However, the question that often arises is whether these tests can be erroneous, potentially leading to unjust convictions or penalties.

The reliability of blood tests

Blood tests have a reputation for being the most accurate method for determining BAC levels. They measure the actual alcohol concentration in a person’s blood, leaving little room for error in theory. However, various factors can still lead to inaccuracies.

One factor is the timing of the test. Alcohol absorption is not instantaneous, and it takes time for BAC levels to peak. If a blood test occurs too soon after a person’s last drink, the BAC may be lower than it would be at its peak, potentially leading to a false impression of sobriety.

Another concern is the potential for contamination. If authorities do not handle or store the blood sample correctly, they risk compromising it. That could result in an inaccurate BAC reading.

Breath tests and their limitations

Breath tests estimate BAC levels by measuring the alcohol content in a person’s breath. While these tests are popular for their convenience, they are not without their own set of potential inaccuracies.

One significant issue with breath tests is the possibility of calibration errors in the device. Regular maintenance and calibration are necessary to ensure accurate readings. Improper calibration can produce skewed results, leading to incorrect DUI charges. A falsely accused person in Mississippi could face license suspension for up to 120 days for a first offense, among other penalties.

Another factor is the potential for mouth alcohol. This can occur if a person has recently consumed alcohol, used mouthwash or has certain medical conditions. The presence of mouth alcohol can lead to an overestimation of BAC levels.

These potential inaccuracies highlight the need for a comprehensive approach in DUI cases, combining the results of these tests with other evidence and observations to ensure a fair and just legal process. It is necessary for law enforcement agencies to maintain the highest standards in test administration and equipment calibration to minimize the risk of erroneous results.