Hi, I am a 42 yr old female. I have itchy skin on my arms , stomach, scalp and neck. I also have a thirst and can get a bit light headed and forgetful. I have an appointment booked for today for my doctor, but wondering what sort of tests he will take. Should i be expecting to get a blood test taken ? Will it affect the test if I have eaten anything, as the appointment is later on in the day? I take 1 multi vitamin with iron supplement and 1 cod liver oil capsule. Could these affect any tests?