Not only the medical personnel is very often unable to properly measure the blood pressure, they also cannot properly take blood sample for potassium. They put tourniquet and order patients to pump their fist, so that the veins appear, but that cause muscles to release potassium into the bloodstream, causing elevated levels and misdiagnosis leading to incorrect treatment. I make people aware of that, and it should be widely spread so that doctors and nurses have the knowledge that they sometimes unwittingly cause harm.