| Marker | Gabriel optimal | Typical lab range | Functional range |
|---|---|---|---|
| Sodium | 138 to 142 mmol/L | 134 to 144 | 135 to 142 |
What sodium measures
Sodium helps control fluid balance, acid-base balance and how nerves and muscles work. Your kidneys and hormones keep it in a tight range. When the number moves, it usually means the amount of water in your blood has changed relative to the sodium.
It is usually tested with chloride, potassium and CO2 in an electrolyte panel or a CMP. Many labs use roughly 134 to 144 mmol/L, and ranges vary by lab.
What low sodium (hyponatremia) can mean
- Fluid retention that dilutes sodium, as in heart failure, cirrhosis and kidney disease.
- Medications, especially diuretics (water pills), SSRI antidepressants and some over-the-counter pain relievers.
- Losing fluid and salt through vomiting or diarrhea.
- SIADH, a condition where the body holds on to too much water, which can come with some brain and lung diseases and certain cancers.
- Hormone problems, such as an underactive thyroid or Addison disease.
- Very large amounts of fluid, for example heavy beer drinking or long endurance events without replacing electrolytes. Drinking a lot of water rarely causes it when the kidneys work normally.
Very high blood sugar can also pull water into the blood and lower the sodium reading, so glucose is checked at the same time.
What high sodium (hypernatremia) can mean
- Dehydration, from not drinking enough, diarrhea or diuretics. This is the most common reason.
- Adrenal gland disorders and kidney disease.
- Diabetes insipidus, an uncommon condition where the kidneys can't hold on to water.
Symptoms of high sodium include strong thirst, passing very little urine, confusion and muscle twitching.
What to do with an abnormal result
- Don't try to fix the number with salt or water on your own. Correcting low sodium too fast can cause lasting nerve damage, so a clinician sets the pace.
- Bring a full medication list, including diuretics, antidepressants and pain relievers. Don't stop any medicine unless your clinician says so.
- Mention recent vomiting, diarrhea, heavy sweating or how much you drink in a typical day.
- Ask about follow-up tests. These may include glucose, kidney and thyroid tests, and urine sodium and concentration, which help find the cause.
Get emergency care if abnormal sodium comes with confusion, seizures, trouble waking up, a severe headache, or severe vomiting or diarrhea. Very low sodium can cause brain swelling, and very low or very high sodium can be life-threatening.
Common questions
What is a normal sodium level?
Many labs use about 134 to 144 mmol/L (the same as mEq/L), and ranges vary by lab. Gabriel's optimal range is 138 to 142 mmol/L.
What sodium level is dangerous?
Below 135 mEq/L counts as low. Risk rises the lower or higher it goes and the faster it changes, and severe changes can cause seizures or coma. Any abnormal result with confusion or seizures needs emergency care.
Can drinking too much water cause low sodium?
It can, but it is uncommon when your kidneys work normally. Risk is higher during long endurance events without electrolyte replacement, with heavy beer drinking, or with conditions and medicines that make the body hold water.
Does eating salt raise my blood sodium?
Blood sodium mostly reflects the balance of water to sodium in your body, so it is not a good measure of how much salt you eat. A low result usually means extra water, not too little salt in your diet.
Which medications can lower sodium?
Diuretics, SSRI antidepressants and many over-the-counter pain relievers can lower sodium. Your clinician may check sodium if you take them.
Sources
- Sodium Blood Test MedlinePlus, U.S. National Library of Medicine
- Hyponatremia Cleveland Clinic
- Electrolyte Panel MedlinePlus, U.S. National Library of Medicine
- Hyponatremia Merck Manual Professional Edition
This guide is general information, not medical advice. It does not replace a visit with a licensed clinician. Gabriel membership is not health insurance.