If all the parties agreed on the need for further samples to be taken, the application could be made in writing to the judge who had conduct of the matter. (newlawjournal.co.uk)
If a need arose for further samples to be taken, that should be arranged only with the approval of the court. (newlawjournal.co.uk)
The law in Canada has been that the results of such a test could only be used to form just cause for further detention and grounds to demand further samples of blood or breath. (vancouvercriminallaw.com)