Final answer:
Acknowledge her emotions and provide reassurance that the blood draw will be quick and painless.
Step-by-step explanation:
The best thing to say to the patient who does not want to extend her arm for the third set of blood draws for a glucose tolerance test (GTT) is to acknowledge her emotions and provide reassurance. You can say something like, "I understand that you're feeling upset right now. Taking blood can be uncomfortable, but it's an important part of the test. I assure you that I will make it as quick and painless as possible." By acknowledging her emotions and reassuring her, you can help to alleviate her concerns and build trust.