Choosing between a DUI blood or breath test is a difficult decision that can call for a deep understanding of how the human body absorbs and eliminates alcohol, the issues around the accuracy and precision of the tests, and what you think your blood alcohol level might be. Blood Tests In general, blood tests are more accurate than breath tests. If you know you are likely well below the legal limit, then blood is better. Additionally, unlike breath tests which are conducted on scene by the police officer, a blood test usually takes place at the police station or jail and is performed by a phlebotomist. If you didn’t consume alcohol for some time prior to the driving, then the additional time needed to administer the blood test would likely lead to test results much lower than the actual blood alcohol level at the time of driving.  A blood sample can be retested by your attorney at an independent lab. A breath test does not retain a sample and cannot be retested. The independent retesting of the blood can examine the blood alcohol level and can also be used to attack the validity of the blood test if there are issues with the amount of preservative in the sample, evidence of microbial growth, or problems with how the blood sample was obtained, handled, and stored. Breath Tests If the driver suspects they are well over the limit, a breath test may be a better choice as it could give their attorney more room to attack the test results. The Breathalyzer is usually administered much closer to the time of driving than blood tests. If the driver finished drinking right before driving and getting pulled over, alcohol is likely still being absorbed into their blood stream. So the Breathalyzer could show a lower result than the blood test, which is given later, at the station, after the alcohol has been absorbed and your blood alcohol level has risen. Your attorney may be able to use your rising blood alcohol level as a defense to drunk driving.  Non-Alcohol DUI If you are arrested for DUI and have taken prescription or recreational substances that can impair driving, know that if you choose a blood test, your blood can be tested for other substances other than alcohol. So you may prefer the breath test to avoid facing a DUI based on the combined influence of alcohol and drugs. However, if the officer believes you consumed drugs, you may be required to take the blood test.