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

How do you read the DUI Breath Test Strip?

On Behalf of | Oct 25, 2016

You read the DUI breath test strip from the top down.  That strip along with the precautionary checklist are important to understand the breath test result and whether the machine was working properly.  The DUI breath test strip is not generated from the portable field PAS breath test, but comes from the official testing equipment at the jail, police department, or can be in the field with a DUI Checkpoint.

The DUI breath test strip identifies the arresting agency, test date/time, operator, test subject, reference number and 15 minutes of pre test observation of the subject.  This pre test observation insures the subject does not ingest alcohol or other fluids, regurgitate, vomit, eat or smoke prior to the breath test as those things could result in an invalid test.  The strip also states the “Dry Gas” target which is the known sample the machine tests before and after the subject blows in order to verify the machine is properly calibrated and working.

The officer giving the test will run a blank air sample to zero the machine, labeled BLK, then the standard or STD (dry gas calibration check value) is run and must test plus or minus .01 of the known value to be within calibration.  Then the subject or SUBJ blows and a result is indicated, the machine is zeroed again with a blank (BLK), then the subject (SUBJ) blows a second time.  The two subject results must be within .02 of each other to be a valid result and the lower value is then cionsidered the official test result for the subject.  The machine is zeroed again with a blank (BLK) and the standrad(STD) are run again to verify calibration after the test.

There are other regulations in Title 17 which set further requirements for testing.  Blood alcohol levels ar always changing, going up or down depending on the drinking pattern.  It is the level while driving which is critical and may be calculated from a later test.  Alcohol breath analysis has other issues as far as accuracy and you should consult an experienced DUI Defense lawyer to explain possible issues and considerations in any DUI case.  Call Christoph Law Offices at 760-670-3885 for a free consultation.  Located across from Vista Courts for over 34 years, we have been providing the highest level of personal professional DUI Defense representation.



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I highly recommend Christoph Law Offices to everyone. Nick is a true professional who will go above and beyond for his clients. Thank you!
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