What is Sodium?
Sodium is the main salt outside your cells. Together with water it sets your fluid balance, and through that your blood pressure, nerve signalling, and muscle function. Your kidneys and hormones hold the value within a narrow range, regardless of how much salt or water you take in. An abnormal value is therefore almost never about how much salt you eat — it is about your water balance. Low sodium usually comes from retaining too much water or losing too much fluid; high sodium almost always from dehydration.
Why is Sodium relevant?
In healthy people sodium is rarely the marker that demands immediate action, but it adds context in a few situations. People on water pills, with kidney problems, or athletes who drink large volumes of water without replacing salt are at higher risk of a low value. The value becomes more relevant with persistent symptoms such as dizziness, headaches, or confusion, and as part of broader investigation of your kidney, thyroid, or adrenal function. A stubbornly low value is a logical reason for further investigation with a doctor.
Sodium high or low — what it means
Read sodium alongside potassium, creatinine, and eGFR, and in the context of hydration and medication. A single mildly abnormal value without symptoms is usually not a problem — a repeat test under normal conditions gives a more reliable picture. Markedly elevated blood glucose can artificially lower the measured sodium value. A persistent, unexplained deviation warrants investigation into the underlying cause; that is medical territory.
Sodium reference ranges
Cut-offs vary slightly by lab and method — always check the reference range on your own report. Markedly elevated blood glucose can lower the measured sodium value.
Educational information only — not medical advice. Consult a healthcare professional for clinical decisions.
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