Well, I had an extracellular minerals test. This is different than a blood test, they scrape the back of the tongue to break open some cells and measure whats in and around them.My Mg+ was normal...I was slightly surprised by this. But my potassium was low. Not terribly low, but low enough for my doc to put me on an extended release K pill called Potassium CL 20MEQ ER Tablets. I take one a day.Low Potassium can cause lots of my twitching and other symptoms. I also have had PVC's (heart palpitations) for years.I just started, but I thought I would let all of you know.Scott