Hypokalemia By James L Lewis III, MD, Brookwood Baptist Health and Saint Vincent's Ascension Health, Birmingham Reviewed / Revised Sep 2021 | Modified Sep 2022 View Patient Education Etiology Symptoms and Signs Diagnosis Treatment Prevention Key Points Topic Resources QT Interval Correction (EKG) ECG patterns in hypokalemia Hypokalemia is serum potassium concentration < 3.5 mEq / L (< 3.5 mmol / L) caused by a deficit in total body potassium stores or abnormal movement of potassium into cells.