Understanding Breath and Blood Alcohol Testing Procedures

April 28, 2024 8:19 am
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If you’re facing a drink-driving charge, understanding the procedures surrounding breath and blood alcohol testing is crucial. These tests play a pivotal role in determining your guilt or innocence, and even minor errors or irregularities can have significant legal implications. That’s why it’s essential to work with an experienced legal team like Driving Solicitors, who specialise in drink-driving cases and can provide expert guidance throughout the process.


Breath Alcohol Testing

Breath alcohol tests are the primary method used by law enforcement to detect the presence of alcohol in a driver’s system. There are two types of breath tests: roadside and evidential.

Roadside breath tests are conducted at the side of the road using a hand-held screening device. If the test indicates the presence of alcohol, you may be arrested and taken to a police station for an evidential breath test.

Evidential breath tests are conducted at the police station using an approved breathalyser machine. You will be required to provide two specimens of breath, and the lower of the two readings will be used as evidence. Failure to provide a valid specimen or registering a reading above the legal limit can result in serious consequences, including a driving ban and criminal charges.


Blood Alcohol Testing

In certain circumstances, such as if you are unable to provide a breath sample or if you were involved in a serious accident, a blood sample may be required to determine your blood alcohol level.

The process involves a qualified medical professional taking a blood sample, typically from your arm, using an approved container. The sample is then sent to a laboratory for analysis, and the results are used as evidence in your case.

A positive blood alcohol result can have severe legal implications, including a driving disqualification and potential criminal charges.


Challenging Test Results

While breath and blood alcohol testing procedures are designed to be accurate and reliable, there are instances where the results may be challenged. Potential grounds for challenging test results include procedural errors, faulty equipment, or medical conditions that could affect the readings.

However, successfully challenging test results requires a thorough understanding of the relevant laws and regulations, as well as the ability to build a compelling legal argument. This is where the expertise of a reputable firm like Driving Solicitors can be invaluable. Their team of experienced solicitors can evaluate the strength of any potential challenge and provide skilled representation in court.


Understanding Legal Limits

In England and Wales, the legal blood alcohol limit for drivers is 80 milligrams of alcohol per 100 millilitres of blood (0.08%). However, lower limits apply to professional drivers (0.02%) and drivers under the age of 20 (0.01%).

It’s important to note that various factors, including gender, weight, and metabolism, can affect an individual’s blood alcohol level. Additionally, even being slightly under the legal limit can impair your ability to drive safely.



Facing a drink-driving charge can be a daunting experience, but understanding the procedures surrounding breath and blood alcohol testing can help you navigate the legal system more effectively. Remember, even minor errors or irregularities in the testing process can have significant implications for your case.

If you find yourself in this situation, don’t hesitate to seek the expertise of Driving Solicitors. Their team of knowledgeable and experienced solicitors specialises in drink-driving cases and can provide the guidance and representation you need to achieve the best possible outcome. Contact us today to discuss your case and protect your rights.