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  • Former Deputy San Diego City Attorney
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Attorneys William R. Christoph & Nicholas W. Christoph

Are DUI Breath Tests accurate in Carlsbad arrests?

On Behalf of | Oct 16, 2013

A DUI breath test can be fairly accurate in Carlsbad arrests and all othe “drunk driving” arrests.  The official test is usually given at the police station or Vista Jail in North County.  The field breath machine is not as accurate.  The breathalyzer is maintatined and caliberated by the San Diego Crime Lab and these records are available to attorneys.  The Officer must be trained on the equipment and go through a checklist when administering a DUI breath test.

This procedure requires the officer to observe the arrestee for 15 minutes prior to giving the DUI breath test to ensure that he or she does not not burp, regurgitate, eat or smoke.  Then a blank air sample is run through the machine to zero the machine before running a known standard of .08 to test accuracy.  It must read .08 plus or minus .01 to be in tolerance.  Then the machine is zeroed again and the subject blows twice.  The machine is zeroed after each blow.  The results must be plus or minus .02 of each other to be valid.  The lower of the two subject values becomes the official blood alcohol level. 

The breathalyzer only measures the last little bit of exhale which is deep lung air and then with certain medical mathematic assumptions converts the breath sample to a blood alcohol (BA) level.  The breath machine and results has more room for impeachment than a blood test, but can still be considered accurate.  Blood alcohol levels are constantly changing, either rising or falling.  The BA then still has to be extrapalated to time of driving.  Call Christoph Law Offices for a free consultation at 760-670-3885.  They have handled over 3000 DUIs and have neen located directly across from Vista Courts for over 30 years.



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