Re: does fasting effect tsh?
I honestly don't believe fasting would affect TSH. Some say certain types of food can affect TSH levels. I have personally seen no indication of that, but if you think that's true, why not just be constant about your diet during the testing process. If you fast for a test, then fast for the next. Like that ...
Of all the reasons I have seen published for a fluctuating TSH, the most likely I have seen are:
Fluctuations of other hormones (estrogen, for example)
Other prescription drugs
Stress or illness
Can you persuade your doctor to test thyroid antibodies? Some docs who don't want to start treatment with a TSH <10 may reconsider when symptoms are very convincing and/or antibodies are high.