Final answer:
A phlebotomy technician should collect the blood specimen at least 2 hours after the patient receives a dose of the medication.
Step-by-step explanation:
When collecting a blood specimen to measure the trough level of a medication, the phlebotomy technician should collect the specimen at least 2 hours after the patient receives a dose of the medication. This is because the trough level represents the lowest concentration of the medication in the patient's bloodstream, which occurs just before the next dose is administered. By waiting at least 2 hours after the previous dose, the technician ensures that the medication has reached its lowest level.