Final answer:
Respect the patient's privacy and do not disclose the glucose level without the patient's consent.
Step-by-step explanation:
When performing a glucometer reading for a young adult while the parent is in the room, it is important to respect the patient's privacy and confidentiality. According to medical ethics, healthcare professionals should obtain the patient's consent before disclosing any medical information to a third party, including the parent. Therefore, in this situation, you should politely explain to the parent that you are unable to disclose the patient's glucose level without the patient's consent.