Select a language

Blood and urine tests

Region: Ontario Answer Number: 772

The police will normally demand a breath sample if they believe a driver has consumed alcohol. In certain situations, however, they have the legal right to request a blood or other bodily fluid (urine or oral fluid) sample. In the case of a blood sample, this must be done under the supervision of a trained medical technician.

When can the police request a blood, urine or bodily fluid sample?

If the police suspect you of being impaired, they can test for alcohol or drug impairment three ways: through a breath sample (for alcohol impairment only), an oral fluid sample, or by conducting a Standardized Field Sobriety Test (SFTS). If you fail a roadside test, you can be taken to the police station (or a medical facility) for additional testing, which can  include providing a further evidentiary breath test, and a blood sample taken by a medical technician. The police can also demand a bodily fluid sample to confirm their findings if you fail a drug recognition evaluation (DRE) that is done at the police station.

In addition, the police are permitted to request a blood or bodily fluid sample if they have a good reason to believe you were driving after having consumed alcohol or drugs and you will not be able to provide a proper breath sample. For example, if you were in a car accident and were injured or rendered unconscious, you may not be in a condition to give the police an adequate breath sample. A doctor must be satisfied that taking the samples will not endanger your life or safety.

Drug recognition evaluation

In Canada, drug-impaired drivers can be detected by police officers who are trained and certified as Drug Recognition Experts (DREs). Evaluation for drug impairment includes sobriety tests that are similar to tests for alcohol impairment, taking blood pressure, oral body temperature and pulse, and measuring pupil size in different lighting conditions.

Failing a test

If you fail a blood or bodily fluid test, you can be charged with other related charges such as impaired driving and driving while exceeding the legal blood alcohol limit. Dangerous driving and criminal negligence may also arise, depending on the facts.

Drivers who fail to comply with a drug recognition evaluation, or who comply and are deemed to be under the influence of drugs, will also be subject to criminal charges that carry the same penalty as driving while impaired by alcohol.


You have the right to talk to a lawyer before letting the police conduct an evidentiary breath test, provide a blood sample, or participate in a drug recognition evaluation. However, if you refuse to provide a sample, you can be charged with the offence of refusal to comply with demand for sample.

To erase your criminal record, call toll-free 1-866-362-7143 or learn more at All Cleared. It’s easier than you think.

If you have been charged with any criminal offence, and need to hire a criminal defence lawyer, contact our preferred criminal law experts:

The Criminal Law Team

Calvin Barry Criminal Lawyers

The Criminal Law Team Criminal ONThe Criminal Law Team Criminal ON

Calvin Banner 1

All Cleared Criminal Law ONAll Cleared Criminal Law ON

Was your question answered?


You now have 4 options:

Was your question answered?

Yes    No

What information would you like to see added?

Submit an Edit Request

What are your changes?*

Page loaded. Thank you