Anatomy and Physiology for Multiple Organ Systems Practice Test

Hyponatremia means there is not enough sodium in the blood, defined by a serum sodium level below about 136 mEq/L. This usually reflects an excess of water relative to salt, diluting the sodium concentration rather than a large loss of sodium on its own. So the description of a blood sodium below 136 mEq/L with an excess of water to salt fits hyponatremia best. In contrast, a high sodium level indicates hypernatremia, a high potassium level indicates hyperkalemia, and a low pH indicates acidosis rather than hyponatremia.