Question

Why toxicology testing is done in urine and saliva not blood?

Answer 1

Answer:

as they are wastes and not required by the body while blood is required

Answer 2

A toxicology test ("tox screen") checks for drugs or other chemicals in your blood, urine, or saliva. Drugs can be swallowed, inhaled, injected, or absorbed through the skin or a mucous membrane. Testing is often done on urine or saliva instead of blood.