is blood sample valid

Hello everyone here. I’m new here and have a question. Maybe one of you knows each other. The following case is constructed: The police bring someone who is under suspicion under alcohol influence to have gone to a clinic for blood collection. Gives to a doctor, however, who is naturally a psychologist but a doctor of the night duty has the test packet. The power to work first on the right arm, gets no drop of blood, only quenching. OK new packet left arm, the same game. Then the suspect goes back to hald. Then we get out the police already the drop of blood. No package there. The doctor leaves the room and sends a sister, which can of course and still a package is not allowed in this case. This also stings the back of the left hand. With success. Proudly she hands over the blood sample to the police officer and goes again. The “doctor” comes back and does the usual tests on his r list. And now my question: Is this blood sample courtable? Thank you in advance for your answers.