I have read that tests for potassium can be inaccurate. how can i trust the results on my recent test? i was very low before, now normal @ 4.0.

Lab error: Potassium blood tests are very sensitive to hemolysis. When a tube of blood is drawn for potassium it needs to be handled properly by lab personnel. If it isn't, the potassium may leak out of cells causing a falsely elevated result. If initial level is drawn in doctors office and too high, it should be repeated at a lab. Lower levels are usually accurate. It's the high ones that are often errors.

Good test: Standard serum chemical test, and while it can be wrong on rare occasion , overall it is very accurate. If done by standard blood draw, no IV fluids, good stick and rapidly to approved lab, you should have high accuracy.