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