I am on up and down dosage of carbrimazole. It requires monthly to six-weekly blood tests with TSH, T4 and T3 done, In August they only did TSH because it was 0.61 and therefore normal. I was concerned. Asked in September for T4 and T3 to be done. T4 was 12.3. Said they did not do T3. Went to GP today as having some palpitations at night and thanks to this site realised probably low T3, Initially GP said 'Oh you TSH and T4 were fine' I said could she look for T3 results. Initially said did not have and then suprised saw I had requested and it had finally come back. It was 3.6 which is low. With her decided to reduce carb to 2.5 which I am pleased with, also going to let endo know.If I hadn't requested these results (knowing how important they are from this site) I would have gone on with low T3. So thank you everyone....!