How reliable are the test results for drink driving? 

Of all the samples that could be given in a drink driving case, a breath sample is the most common and urine is the least. This is because Police guidance advises that urine should only be taken as a last resort, due to the complicated nature of the procedure, the time it takes to collect an evidential urine specimen and the inaccurate and unreliable results often provided by laboratories. On occasions where a breath sample cannot be obtained, or the reading requires further investigation, you will need to provide a blood or urine sample at the police station. 

The first breath test you will usually have to complete is if you are pulled over at the roadside by a police officer because you are suspected of driving under the influence of alcohol. It is done with a breathalyser and takes only a couple of minutes. If your breath reading is under the legal limit of 35mg , you will probably be free to go. If it is borderline or above, or there is an issue with the device,  you will be required to provide additional breath readings at the police station on the evidential breath machine. A person suspected of an alcohol related motoring offence will be required to provide two evidential specimens of breath. The reading with the lower proportion of alcohol will be used as prosecution evidence (if above the legal limit )and the other reading will be discarded.

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The evidential breath testing machines currently in use across England and Wales are around 15 years old. They look more like 1980's fax machines than high-tech analytical devices! Due to their age, they are very demanding in terms of breath volume and the strength at which you have to blow. Some people have reduced lung capacity and may not realise. Others may experience shortness of breath in highly stressful environments. There is a 'knack' to providing a sample of breath and not everyone can get the hang of it. This should not mean you lose your licence.

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Breath alcohol level	Starting point	Disqualification	Disqualification (2nd offence)
36 – 59	Band C fine	12 – 16 months	36 - 40 months
60 – 89	Band C fine	17 – 22 months	36 - 46 months
90 – 119	Community Service	23 – 28 months	36 - 52 months
120 – 150>	12 weeks custody	29 – 36 months	36 – 60 months

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In the majority of cases, yes, however in cases where there is a significant difference between the two breath specimens provided, the results will be deemed unreliable and an alternative specimen for analysis (blood or urine) may then be required. An alternative evidential breath testing device could also be used instead, if one is available. If you feel that your breath test procedure was unlawful, or you disagree with the breath reading result, it is imperative that you seek legal advice as soon as possible so we can challenge the results. 

You may be surprised to learn that you do not have an automatic right to give a blood sample at the police station, even if you ask for it. Section 7(3) Road Traffic Act 1988 says that a blood specimen can only be requested in the following circumstances;

The police cannot charge you with drink driving before the results of the blood test have been obtained, even if your roadside reading was high. You will be released under investigation until the results come back, and do not usually have to return to the police station (unless the police want to interview you). Blood tests can take anywhere from 8 weeks to 6 months. You can continue to drive over this period, unless the police tell you otherwise.

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All blood samples MUST be obtained by a doctor, nurse or registered medical practitioner/healthcare provider

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Blood alcohol level	Starting point	Disqualification	Disqualification (2nd offence)
81 - 137	Band C fine	12 – 16 months	36 - 40 months
138 - 206	Band C fine	17 – 22 months	36 - 46 months
207 - 275	Community Service	23 – 28 months	36 - 52 months
276 - 345>	12 weeks custody	29 – 36 months	36 – 60 months

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Blood tests are probably the most reliable form of testing if they are done within a specific window. Once your body has eliminated alcohol from your system, it would be very difficult to produce a reading which could be used as evidence against you. Blood readings are usually challenged based on how they were obtained, rather than the reading itself. For example, was the blood test lawful? Were you given the statutory warning? Do you have a phobia of needles which was not taken into consideration? Was the sample stored correctly? All of these, if not adhered to could amount to a full defence. As with the breath reading, if you feel that your blood test procedure was unlawful, or you disagree with the results, it is imperative that you seek legal advice as soon as possible so we can challenge the results. 

There is no immediate option to provide a urine specimen at the police station. An officer can only request a sample of urine if;

The law states that you have one hour to provide two specimens of urine. The first sample involves you urinating into a container. This sample is then handed to the officer and discarded by the officer. It is crucial that the officer discards this sample. It cannot be discarded by you and cannot be directly into the toilet. You should then be given a period of time – often around 40 – 60 minutes – to refill your bladder. This means the officer should be providing you with water. 

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The second sample involves you urinating into a container. This sample is then handed to the officer and split into two. Part of the second sample is given to you, the other part is the kept by the officer (this is the part that will be sent to the laboratory).

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urine alcohol level	Starting point	Disqualification	Disqualification (2nd offence)
108 - 183	Band C fine	12 – 16 months	36 - 40 months
184 - 274	Band C fine	17 – 22 months	36 - 46 months
275 - 366	Community Service	23 – 28 months	36 - 52 months
367 - 459>	12 weeks custody	29 – 36 months	36 – 60 months

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It stands to reason that the more you do something, the better you become at it. Many police officers are far less familiar with urine procedures because they carry out so few of them. This can result in mistakes being made. 

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We mentioned above that two samples of urine will be obtained for analysis. The purpose of the first sample is to clear the bladder of urine, since this contains alcohol that has been eliminated from the blood over an unknown period of time. The second sample should be urine which has been freshly formed in the bladder and is therefore a truer representative of a person’s BAC at the time of sampling. Emptying the bladder in the first sample is fundamental to the reliability of the second sample, but the police procedure forms do not explain this; they merely ask for the time in which the first and second sample was taken. This means that suspects may not fully empty their bladder in the first sample, therefore how can we possibly know whether the second reading (the one that will be used in evidence) is 100% accurate and reliable? This is why it is so important to challenge all readings - in so many cases the police fail to adhere to the correct procedure, and we have the resources to instruct experts to make sure you are getting a fair trial. 

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Next Steps 

If you want more information on drink driving offences, please get in touch for free legal advice on 0151 422 8020.