Beating Positive Breathalyzer Results: Why Breathalyzer Tests Can Be Wrong

 We all know that drinking and driving is never a good idea.  There is no excuse for getting drunk and getting behind the wheel of a car.  However, what if you only had one drink or a sip of alcohol, even none at all, and you tested positive on a breathalyzer test?  This type of thing happens more than you think.  Recently in San Francisco over 1,000 false positive readings were thrown out, and prosecutions overturned because of such results. 

How can Breathalyzers Yield False Positive Results? 

1.        Improper Breathalyzer Calibration

Improper calibration was the main cause of the over 1,000 conviction turnovers in San Francisco last spring.  Every make and model is different, and law enforcement divisions must follow the equipment manufacturer’s guidelines for calibration exactly for the results to be accurate.  In the California incident, the 20 breathalyzer units were supposed to be calibrated every two weeks.  However, San Francisco law enforcement failed to maintain the equipment manufacturer’s guidelines and was forced to overturn hundreds of convictions based on the outcome of the breathalyzer test results.

2.        Alcohol Residue in Mouth

This may sound silly, but a breathalyzer is designed to measure the amount of alcohol saturation from the air in a person’s lungs.  The human body releases alcohol through the lungs as a way of processing and expelling it.  If a person has just taken a sip of alcohol, they will have residual alcohol in their mouths that the breathalyzer assumes is from the lungs.  This can yield a much higher reading than the actual amount of alcohol in the person’s body. Therefore, each breathalyzer recommends that the testing officer wait a certain period of time (usually about 20 minutes) before administering the test for accurate results.  If you have just downed half a glass of wine before getting pulled over, the residual alcohol in your mouth will mislead the breathalyzer into thinking you just drank an entire bottle.

3.        Breathalyzer Interference

Many things can cause false positive readings on breathalyzer tests, the most common being an elevated number of ketones in diabetics’ blood that causes an increase in acetone in their breath.  Some breathalyzer tests are sensitive to acetone and mistakenly register it as alcohol.  Other substances can cause false positive results as well such as paint fumes, chemical fumes, mouthwash, gum, cough syrup, and even herbal supplements. 

4.        Other Breathalyzer Reading Errors

A breathalyzer can also improperly measure BAC during the absorption phase of alcohol consumption. Absorption time varies depending on the person, but it can last anywhere from half an hour to two hours.  In the absorption period, alcohol is not evenly distributed through the blood stream and can yield erroneous breathalyzer results. 

Did You Test Positive for Alcohol on a Breathalyzer Test?

If you tested positive on a breathalyzer test you need to contact a DWI lawyer immediately to start building your defense.  Only an experienced DWI lawyer will have the knowledge and expertise necessary to fight for you in court.  If you are facing DWI or DUI charges after testing positive on a breathalyzer test, hire a DWI  or DUI lawyer today. 

 

 

 

 We all know that drinking and driving is never a good idea.  There is no excuse for getting drunk and getting behind the wheel of a car.  However, what if you only had one drink or a sip of alcohol, even none at all, and you tested positive on a breathalyzer test?  This type of thing happens more than you think.  Recently in San Francisco over 1,000 false positive readings were thrown out, and prosecutions overturned because of such results. 

How can Breathalyzers Yield False Positive Results? 

1.        Improper Breathalyzer Calibration

Improper calibration was the main cause of the over 1,000 conviction turnovers in San Francisco last spring.  Every make and model is different, and law enforcement divisions must follow the equipment manufacturer’s guidelines for calibration exactly for the results to be accurate.  In the California incident, the 20 breathalyzer units were supposed to be calibrated every two weeks.  However, San Francisco law enforcement failed to maintain the equipment manufacturer’s guidelines and was forced to overturn hundreds of convictions based on the outcome of the breathalyzer test results.

2.        Alcohol Residue in Mouth

This may sound silly, but a breathalyzer is designed to measure the amount of alcohol saturation from the air in a person’s lungs.  The human body releases alcohol through the lungs as a way of processing and expelling it.  If a person has just taken a sip of alcohol, they will have residual alcohol in their mouths that the breathalyzer assumes is from the lungs.  This can yield a much higher reading than the actual amount of alcohol in the person’s body. Therefore, each breathalyzer recommends that the testing officer wait a certain period of time (usually about 20 minutes) before administering the test for accurate results.  If you have just downed half a glass of wine before getting pulled over, the residual alcohol in your mouth will mislead the breathalyzer into thinking you just drank an entire bottle.

3.        Breathalyzer Interference

Many things can cause false positive readings on breathalyzer tests, the most common being an elevated number of ketones in diabetics’ blood that causes an increase in acetone in their breath.  Some breathalyzer tests are sensitive to acetone and mistakenly register it as alcohol.  Other substances can cause false positive results as well such as paint fumes, chemical fumes, mouthwash, gum, cough syrup, and even herbal supplements. 

4.        Other Breathalyzer Reading Errors

A breathalyzer can also improperly measure BAC during the absorption phase of alcohol consumption. Absorption time varies depending on the person, but it can last anywhere from half an hour to two hours.  In the absorption period, alcohol is not evenly distributed through the blood stream and can yield erroneous breathalyzer results. 

Did You Test Positive for Alcohol on a Breathalyzer Test?

If you tested positive on a breathalyzer test you need to contact a DWI lawyer immediately to start building your defense.  Only an experienced DWI lawyer will have the knowledge and expertise necessary to fight for you in court.  If you are facing DWI or DUI charges after testing positive on a breathalyzer test, hire a DWI or DUI lawyer today. 

 

 

 

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