Hi can anyone help answer a question for me please. I recently had a blood test and my potassium levels are 5.5 so need to re test on Monday, should I be worried at these results. I have also been diagnosed with under active thyroid last yr and since then my results have been all over. It was my liver last time but has now settled down and this time my kidney. It was also 5.5 last December but nothing was done about it.