POTASSIUM TEST MEASURES THE LEVEL OF POTASSIUM IN THE BLOOD. THE AMOUNT OF POTASSIUM IN YOUR BLOOD IS VERY SMALL THAT EVEN A SMALL INCREASE CAN CAUSE HEALTH PROBLEMS, IF THE SODIUM LEVELS INCREASE THE POTASSIUM LEVELS IN THE BLOOD AUTOMATICALLY REDUCE, DUE TO ALDOSTERONE, A HORMONE PRODUCED BY THE ADRENAL GLANDS, POTASSIUM LEVELS MAY GET AFFECTED.