Breathalyzer Test

Reliability of Breathalyzer Test Results

Just by having a driver’s license and driving in the state of Pennsylvania, did you know that you have given your consent to take a chemical breath test or blood test to determine whether or not you are driving drunk? It is called the “implied consent” law, and every state has one. If an officer pulls you over for suspected drunk driving, you MUST allow a breath, blood or urine test to be performed. If you refuse, your license will be suspended, whether or not you are found to be intoxicated. Specially trained DUI attorney Steven Tabano understands that breath tests are not 100% accurate or reliable. Contact Steven Tabano today to schedule a consultation for your defense to a DUI charge.

How a Breath Test Works

The Breathalyzer was invented in 1954 to measure levels of intoxication through breath analysis. Since that time, many other types of breath tests have entered the market, and the term “breathalyzer” has stuck to include all types of breath analyzers. There are four main scientific methods used by different breath analyzers to measure the BAC in a person’s blood:

Chemical Analysis—measures amount of alcohol on one’s breath by chemical reaction.
Infrared Spectroscopy—Because molecules absorb electromagnetic radiation at certain specific, unique wavelengths, the amount of ethyl alcohol in one’s breath can be accurately read by measuring the degree of absorption and energy loss from the infrared energy beam.
Gas Chromatography –not widely used with a breath test.
Fuel-Cell Detection—amount of alcohol concentration is determined by measuring the electrical reaction caused by alcohol oxidation.

Vulnerabilities of Breath Tests

Because breath tests are administered by people, there is always going to be the possibility of error. A competent defense attorney can use information known about blood alcohol content and related breath alcohol content to help determine whether or not your breath test was done correctly, and whether or not the results should be considered reliable. Possible arguments a defense attorney could use include:

The breath tests’ assumption of a 2100-to-1 blood-to-breath ratio may not be scientifically reliable, although courts generally prevent argument related to the breath-blood ratio, also known as the partition ratio.
The test was not administered correctly; for example, the administrator did not warm up the machine to the correct operating temperature or ensure an adequately deep lung sample.
The test administrator was not properly trained or qualified.
The equipment was not maintained properly, calibrated correctly or cleaned adequately.
The result was affected by some characteristic of the driver, such as age; lung function; overall strength and size; a disease or condition such as asthma, diabetes, eardrum rupture, ketosis, emphysema, bronchitis, dental issues, fever or harelip; shock or trauma; certain types of special diets; or hiccupping, burping, vomiting or hyperventilating. Even severe heartburn could have made the breath results unreliable.
The test administrator did not continuously observe the driver for an adequate period before the test to prevent him or her from putting anything into his or her mouth that could affect the result. For example, a product used in the driver’s mouth, such as mouthwash or adhesive, or lip ointment could have affected the test result.
Police radio operation generated electromagnetic waves, causing radio frequency interference (RFI) with the testing equipment.
The driver was exposed to a gas or vapor before the test that made it unreliable, such as during painting, floor sanding, varnishing or other activity with chemical exposure. Similarly, an outside environmental cause in the surrounding air could have caused a high breath test result.


By driving in Pennsylvania, you are implying consent to giving a breath test if asked by an officer that has pulled you over for suspicion of driving drunk. The refusal of this test could result in more severe penalties than failing the test. The test, although considered a reliable measurement of alcohol in the blood by most law enforcement agencies and court systems does have a variety of vulnerabilities that could lead to the results of the test being thrown out of the case. It is in your best interest to have a qualified DUI attorney such as Steven Tabano on your side to defend against DUI charges.