To determine whether your potassium concentration is within normal limits and to help evaluate an electrolyte imbalance; to monitor chronic or acute hyperkalemia or hypokalemia. Who should be tested? When you have symptoms such as weakness and/or cardiac arrhythmia, or when an electrolyte imbalance is suspected; When should it be tested? At regular intervals when you are taking a medication and/or have a disease or condition, such as high blood pressure (hypertension) or kidney disease, that can affect your potassium level This test should be part of a routine medical exam.