Gentleman
Unlike our part of the world (Pakiland, India, Bangladesh) where there are no consent laws; the IOM and Canadian Immigration has to follow the laws in Canada.  Before you test anyone for anything; a consent is required.  When you go in for your medical, they give you a consent form before blood is drawn.  The form states that they are testing for HIV and VDRL (both sexually transmitted).  No consent is obtained for anything else especially, urine toxicology.
T$