A: My doctor says that I need a blood test.
B: I can help you with that. Just have a seat and roll up your left sleeve.
A: What are you taking my blood for?
B: Your doctor has requested a check of your white blood count.
A: What information does that give him?
B: If your white blood cell count is off, it could signal an infection somewhere in your body.
A: Is a blood test painful?
B: I am putting a tourniquet on your arm to plump up the vein. It will only feel like a little pin prick.
A: Oh, my God, that hurts!
B: That was it! Thank you for coming in today.
n. 传染,影响,传染病