Potassium is important in the normal functioning of muscles and nerves.  Potassium is taken in your diet but the amount in your blood has to be maintained at a safe level.  Too much or too little potassium in you blood can be dangerous.  The kidneys help maintain this balance.  In people with kidney disease, not enough potassium many be excreted leading to high potassium levels in the blood.  In other people, too much potassium may be lost, either through water pills, overactive hormones, electrolyte issues such as low magnesium levels, or even gastrointestinal losses.  Evaluation and management by the nephrologist can lead to adjustment in you diet, and/or adjustments in your medications to helps manage potassium balance.