Sodium is an electrolyte that helps control the balance of fluid in your body and supports nerve and muscle function. Here is how to read your sodium result and what a high or low value can point to, in plain language.
Sodium is a mineral and an electrolyte. It helps your body hold the right amount of water in and around your cells, and it plays a part in how your nerves and muscles work. Your body keeps blood sodium within a narrow range, mostly by controlling how much water you hold on to.
Sodium is reported in millimoles per litre (mmol/L), which is the same as milliequivalents per litre (mEq/L) for sodium. A normal blood sodium level is usually around 135 to 145 mmol/L. Because the number reflects the balance between sodium and water, a result outside this range is often more about body water than about how much salt you eat.
A low sodium level, called hyponatremia, can happen with certain medicines, kidney or heart conditions, or when the body holds too much water. A high level, called hypernatremia, often relates to not enough water rather than too much salt. Both are read in the context of your symptoms, other electrolytes, and your overall health.
Upload a photo or PDF of your metabolic panel and Mednex reads your sodium and the rest of your electrolytes back to you in plain language, then tracks them over time.
Decode my labsContent last reviewed 9 July 2026. Reference ranges vary by laboratory; always read your results against the range printed on your own report.
This page explains a common lab marker in general terms using public information from the U.S. National Library of Medicine and other NIH sources. It is educational and is not a diagnosis or medical advice. Reference ranges differ between laboratories and the meaning of a result depends on your age, sex, medications, and overall health. Always discuss your own results with the clinician who ordered them.