In Western Australia, under the Road Traffic Act 1974, a police officer can require you in certain circumstances to give a sample of your blood for determining whether you have committed a criminal offence of driving a motor vehicle with alcohol in your blood, or under the influence of an illicit drug or whilst drug impaired. If you refuse to give a blood sample when required to do so, you may commit a criminal offence.
A police officer may require you to undertake a breath analysis if the circumstances suggest that you have driven a motor vehicle under the influence of alcohol. For example, if you were stopped at a random breath testing station and a preliminary test suggested you had more than the prescribed concentration of alcohol in your blood, you might be asked to give a breath analysis test. You might also be asked to give a breath analysis test if you could not or refused to take part in a preliminary breath test, if you could not give a sufficient breath sample for preliminary testing, or if a police officer believes on reasonable grounds that you have committed a certain kind of offence (e.g. dangerous driving causing bodily harm).
If you cannot provide a sample for breath analysis because of a physical condition, you may be directed to allow a medical practitioner or a nurse to take a sample of your blood for analysis. You may also be required to give a sample of your blood if the breath analysis machine is not working. If the police officer reasonably believes you have committed a certain kind of offence and requires you to take a breath analysis, you may still be required to give a sample of your blood for analysis even if the breath analysis was negative. However, you can only be required to give a sample of your blood within 4 hours of the incident of driving giving rise to the police direction.
If you undergo a driver assessment and the assessment indicates you were drug impaired while driving a motor vehicle, or if you refused to undergo a driver assessment, a police officer may require you to give a sample of your blood for analysing whether you were drug impaired. However, such a sample cannot be required outside of the 4 hour period immediately after the period of driving giving rise to the requirement. If you cannot provide a sample for oral fluid analysis (which is undertaken to check whether you have an illicit drug in your system) because of your physical condition, a police officer may require a blood sample to be taken.
There are very prescriptive rules in the Road Traffic (Blood Sampling and Analysis) Regulations 1975 for how a sample of blood is to be taken. For example, there are specific rules for what sampling equipment must be used, including the requirement for a syringe to be sterile. The sampling equipment must be prepared by a technologist who will then complete a form certifying the equipment is sterile. The blood sample must then be taken by either a medical practitioner or a registered nurse, using only the sampling equipment. If the equipment’s package is not sealed or intact, they must not use it. If only one sample is taken, half of the sample must be given to the person giving the sample. If two samples are taken, one must be given to them. The person taking the sample and the person who analyses the blood must complete certificates that each of those steps have been taken. The method for analysing the blood is also prescribed by the regulations. The sample cannot be used to take a copy of your DNA.
If a blood sample shows you have a prescribed concentration of alcohol or a drug in your system, it can be used as evidence to demonstrate that fact. The form signed by the technologist, certifications by the medical practitioner or nurse who took the sample, and certifications from the analyst who analysed the blood (see above) can also be used as evidence the procedure for taking and testing a blood sample was complied with. If the sample was not analysed in accordance with the regulations described above, then it is not deemed to be your blood alcohol content at the time it was taken. If you are convicted of a DUI offence for alcohol, there are specific rules for calculating what the amount of alcohol was in your blood at the time the offence was committed, based on the time the blood sample was taken.
If you refuse to give a sample of your blood and there is no substantial reason why you did so, you will commit an offence. The penalty for the offence varies depending on whether it was a first offence.