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Chemical Test

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Definition - What does Chemical Test mean?

Driver's blood alcohol concentration can be measured with three tests (blood, breath and urine). The most common chemical tests are breath and blood tests. State laws can vary, but some states allow law enforcement officers to determine the test which is required.

  • Urine Tests - Urine tests are the least common blood alcohol tests. Problems often arise with reliability in sample collections and testing procedures. Urine tests may be used to reliably detect certain types of illegal narcotics.
  • Blood Tests - Blood tests, although invasive, are reliable. Some states do not allow law enforcement officers to gather blood samples. Drivers who have been arrested and who have submitted to a blood test should consult with a DUI attorney. Problems may arise with blood collection, the chain of custody of the blood sample or the storage of the blood.
  • Breath Tests - Breath tests are the most common type of chemical test for evaluating a driver's BAC, but they may be less accurate at determining the actual amount of alcohol in a driver's blood. Drivers who have been arrested for DUI and have submitted to a breath test should contact a DUI lawyer. DUI attorneys may be able to prove the breath sample was collected improperly or the test results were invalid due to faulty breathalyzer machines or human error. Some states will use a portable breathalyzer machine to perform a "preliminary breath test". These machines may not provide evidence which can be admissible in court but may provide probable cause for a DUI arrest. Other states use Evidentiary Breath Tests which are more common and provide DUI evidence which can be admitted in DUI court.

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