Suspected drugs: the procedure with saliva test and clinical examination.
Where impairment by narcotics is suspected, a graduated procedure follows. First a saliva pre-test can be carried out, then a clinical examination by a medical officer and finally a blood draw. From a legal perspective it is important to know that there is no fixed limit, the question is whether you were actually impaired. Provide your personal details, but you do not have to say anything on the matter.
A blood draw cannot be enforced by coercion, but a refusal leads to a higher penalty. The exact documentation of the clinical examination is a central point of the defence later.