Sodium Blood Test
Reviewed
A sodium blood test measures the amount of sodium in your blood. Sodium is an electrolyte that helps control fluid balance, nerve function, and muscle function. Abnormal levels may indicate kidney problems, dehydration, or other conditions.
Preparation and collection
Your provider will let you know how to prepare. You may need to stop taking certain medicines before this test. You may also need to fast (not eat or drink) for several hours before the test. Do not stop any medicines unless your provider tells you to.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- Results that are not in the normal range don't always mean a medical condition that needs treatment.
- Certain medicines, age, sex, and medical conditions can affect sodium levels.
- The test is often interpreted with other electrolyte tests.
- A single abnormal result may be due to temporary factors.
What to do next
If your results are abnormal, your provider will likely repeat the test and/or order additional tests such as an electrolyte panel, basic metabolic panel, or comprehensive metabolic panel to help diagnose the cause. Treatment will depend on the underlying condition. Do not change your medicines without consulting your provider.