Does this test have other names?
What is this test?
This test measures the levels of sodium in your blood. Sodium is a substance your body's cells need to work normally. Sodium helps make sure that your nerves and muscles can work as they should. Sodium is also important because it helps maintain the right balance of fluids in your body. The kidneys help keep sodium at a healthy level. You can get the sodium you need through your diet. But it's easy to take in too much sodium through your diet. When your body has too much sodium, your kidneys can't remove enough of it. Sodium collects in your bloodstream. This can lead to high blood pressure, which can cause other problems.
Too much sodium in the blood is called hypernatremia. Too little sodium in the blood called hyponatremia. Hypernatremia can occur when you lose too many fluids. This can happen from sweating too much, vomiting, or diarrhea. Hyponatremia can occur when you drink large amounts of water or if you have problems with your kidneys that affect your ability to urinate.
Why do I need this test?
You may need this test if your healthcare provider thinks you have an imbalance of fluids and sodium. You may have symptoms such as:
The test can check for:
Or you may need this test if you:
What other tests might I have along with this test?
You may need other tests along with a sodium blood test. You may have tests to look at:
What do my test results mean?
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
Normal sodium levels are usually between 136 and 145 millimoles per liter (mmol/L). Blood sodium levels below 136 mmol/L may mean you have low blood sodium (hyponatremia). Blood sodium levels greater than 145 mmol/L may mean you have blood sodium levels that are too high (hypernatremia).
How is this test done?
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.
If your blood sample is collected incorrectly, your test results may be affected. Having high blood sugar (hyperglycemia) can also affect your test results.
Taking some medicines can also affect your test results. These include diuretics and nonsteroidal anti-inflammatory medicines such as ibuprofen.
How do I get ready for this test?
Your healthcare provider will tell you what you need to do before this test. You may need to not have food or water for several hours before the test. You may need to not take some of your medicines on the day of the test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.
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Instructions for Hypernatremia
You have been diagnosed with hypernatremia. This means you have too much sodium (salt) in the blood. It can be caused by a high salt intake. But it's more often due to fluid loss. Loss of too much fluid can occur if the kidneys excrete too much urine. This is called polyuria. Fluid loss can also be caused by excessive sweating. This can happen during hot weather or exercise. It can be caused by diarrhea or vomiting. It can also be caused if you don't drink enough water. If not treated right away, it is a seriouis problem that can cause a seizure or a loss of consciousness. It can also lead to death.
Symptoms of hypernatremia include:
Limit all foods that are high in sodium, including:
Other home care
Follow up with your healthcare provider, or as advised. Your healthcare provider will need to watch your condition closely. You may need extra care if you have a health condition that causes your hypernatremia.
When to call your healthcare provider
Call your healthcare provider right away if you have any of the following:
Hyponatremia means low sodium levels in the blood. This condition most often occurs after prolonged vomiting or diarrhea, which causes your body to lose too much water and sodium. It can also result from drinking excess amounts of water or the use of diuretics (water pills). Rarely, it can be associated with disorders of your endocrine system, as side effects of illicit drug use (ecstasy), as a complication of some cancers especially small cell lung cancer, or as a complication of renal and liver disease or heart failure.
Mild hyponatremia causes no symptoms. It is only discovered with a blood test. As sodium levels in the blood decreases, symptoms begin to appear. This includes weakness, confusion, muscle cramping and seizures.
Follow up with your healthcare provider for a repeat blood test within the next week, or as advised.
When to seek medical advice
Call your healthcare provider if any of the following occur:
Instructions for Hyponatremia
You were diagnosed with hyponatremia, which means your blood level of sodium (salt) is too low. Salt is needed for the body and brain to work. Very low blood levels of sodium can be fatal. Symptoms can include headache, confusion, fatigue, muscle cramps, hallucinations, seizures, and coma. You have been treated to raise your blood levels of sodium. These instructions will help you care for yourself at home as you have been instructed.
To help prevent hyponatremia:
Follow up with your healthcare provider, or as advised.
When to call your healthcare provider
Call your provider right away if you have any of the following:
Disclaimer: The UCLA Health System cannot guarantee the accuracy of such information. The information is provided without warranty or guarantee of any kind. Please speak to your Physician before making any changes.