Table of ContentsView AllTable of ContentsResultsAbnormal-Level RisksReasons to TestNext Steps
Table of ContentsView All
View All
Table of Contents
Results
Abnormal-Level Risks
Reasons to Test
Next Steps
A sodium (Na+) blood test is a standard medical test that checks sodium concentration in your blood. It’s often performed as part of a panel of blood tests. This test is important because having too high or too low a sodium concentration in your blood can cause serious medical problems.
Various medical issues can affect your sodium blood levels. However, this test typicallydoes notprovide good information about whether you should reduce the amount ofsodium in your diet.
Stefania Pelfini, La Waziya Photography / Getty Images
Sodium Blood Test Results
A sodium blood test measures the sodium concentration in your blood. Sodium blood test ranges can be normal, low, or high and are measured in milliequivalents per liter (mEq/L), as shown below:
Your body usually does a good job regulating the amount of sodium in your blood. When levels are off, however, body systems such as your brain and heart can be affected.
Normal Sodium Levels
Low Sodium Levels
If your sodium levels are less than 135 mEq/L, a healthcare provider may tell you that you havehyponatremia, a lower-than-normal sodium concentration in the blood. Severe hyponatremia, which poses an increased risk of serious complications, is defined as 120 mEq/L or less.
Low sodium concentration in the blood is a common medical issue, particularly in older individuals or people who are ill from various medical problems, such as kidney, heart, or liver disease.Certain medications can also cause hyponatremia, including:
Hyponatremia can happen when the amount of water you are taking in is greater than the amount you are losing (e.g., through your urine), and your body can’t sufficiently adapt. It can also happen when you are losing a lot of sodium from your body.
High Sodium Levels
Hypernatremiais a sodium concentration that is too high in the blood, greater than 145 mEq/L. It doesn’t happen as often as hyponatremia, but it is more common in infants, older adults, or anyone without normal thirst mechanisms or lack of access to water.
Hypernatremia can occur when the body loses a lot of water, like throughdehydration. It might also occur with excess vomiting, sweating, or urination.
Certain drugs can also cause it, including:
Less commonly, it can result from extreme sodium intake, like through an intravenous (IV) line in someone in an intensive care unit. It’s very uncommon for a person to have hypernatremia just from their dietary intake of sodium unless they also have a medical problem like kidney disease.
Hydration and Sodium LevelsPeople with hyponatremia or hypernatremia may bedehydrated, have normal hydration, or are overhydrated.A sodium blood test does not determine the amount of water in the body. Healthcare providers use a medical history, exams, and other tests to determine this, which influences their treatment approach.
Hydration and Sodium Levels
People with hyponatremia or hypernatremia may bedehydrated, have normal hydration, or are overhydrated.A sodium blood test does not determine the amount of water in the body. Healthcare providers use a medical history, exams, and other tests to determine this, which influences their treatment approach.
Risks of Abnormal Blood Sodium Levels
Sodium levels that are too high or too low can have significant health impacts, particularly when they’re extreme or if the change happens suddenly.
Low Sodium (Hyponatremia) Risks
Having hyponatremia may not cause any symptoms, especially at first. But if it worsens or isn’t corrected, it may cause issues like headache, lethargy, or dizziness. When severe, it may be more likely to cause serious issues, such as:
High Sodium (Hypernatremia) Risks
If present, symptoms of hypernatremia tend to be mild in adults. They might include lack of appetite, vomiting, muscle weakness, and restlessness. However, more severe symptoms, like seizures or coma, are a greater risk in infants or people with very high sodium levels.
Why It’s Done
A sodium blood test is a common test. You might get it as part of a general checkup or if you are being treated at the emergency room or hospital.Other reasons to have a sodium blood test include:
A sodium blood test tells you that the sodium concentration in your blood is high, but it doesn’t explain why. For that, you may need additional tests.
Sodium in the Diet and Sodium Blood Tests
A sodium blood test isn’t a good way to check whether you are getting the right amount ofsodium in your diet. That’s because the body is usually very good at adapting and keeping the sodium concentration in your blood at normal range.
Even if your sodium blood test is normal, you might still get too much salt through your diet, leading to issues like high blood pressure. A better way to check your salt intake is to use a food diary and discuss your results with a healthcare provider.
Many people need toreduce sodium intakein their diet. The following are some ways to decrease dietary sodium potentially:Check labels to find out which foods are high in sodium. Use the percentagedaily value (DV)and the serving size as tools.Look for products labeled as reduced sodium or low in sodium.Avoid canned, prepackaged, and prepared foods and condiments with very high sodium levels. Instead, try to cook meals from scratch.Use less salt at the table or when you are cooking. Try “no-salt” or spice blends to add flavor instead.
Many people need toreduce sodium intakein their diet. The following are some ways to decrease dietary sodium potentially:
Next Steps With Abnormal Sodium Blood Test Results
If your sodium blood test is too high or too low, you may need treatment to restore your sodium to normal. However, the treatment approach may vary depending on whether you have hyponatremia or hypernatremia, its severity and rapidity, whether you are also dehydrated or excessively hydrated, and the underlying cause.
Next Steps for Low Levels of Blood Sodium (Hyponatremia)
Sometimes, a healthcare provider might monitor a low blood sodium level, but you may need treatment in other cases. Some possible treatments might include:
In certain circumstances, a person might need to increase their daily salt intake, but this is often not the case, and for some, it would be detrimental. Check with a healthcare provider to see if you need to increase the amount of salt in your diet.
Next Steps for High Levels of Blood Sodium
Some people with high blood sodium also need treatment. Some examples include:
Many people with hypernatremia may also need to limit their salt intake in the long term, but not necessarily everyone. Talk to a healthcare provider about the next steps.
Summary
Healthcare providers often perform sodium blood tests as part of a general medical evaluation for outpatients or hospitalized people, usually along with other related tests. However, the test is not a good way to monitor your salt intake, which may need lowering in people with high blood pressure, kidney disease, or certain other health conditions.
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Sodium blood test.Wang YJ, Yeh TL, Shih MC, Tu YK, Chien KL.Dietary sodium intake and risk of cardiovascular disease: A systematic review and dose-response meta-analysis.Nutrients. 2020;12(10):2934. doi:10.3390/nu12102934Bernal A, Zafra MA, Simón MJ, Mahía J.Sodium homeostasis, a balance necessary for life.Nutrients. 2023;15(2):395. doi:10.3390/nu15020395UpToDate.Overview of the treatment of hyponatremia in adults.Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015;91(5):299-307.Hoorn EJ, Zietse R.Diagnosis and treatment of hyponatremia: compilation of the guidelines.J Am Soc Nephrol. 2017;28(5):1340-1349. doi:10.1681/ASN.2016101139Kim GH.Pathophysiology of drug-induced hyponatremia.J Clin Med. 2022;11(19):5810. doi:10.3390/jcm11195810Jomova K, Makova M, Alomar SY, et al.Essential metals in health and disease.Chem Biol Interact. 2022;367:110173. doi:10.1016/j.cbi.2022.110173Yun G, Baek SH, Kim S.Evaluation and management of hypernatremia in adults: clinical perspectives.Korean J Intern Med. 2023;38(3):290-302. doi:10.3904/kjim.2022.346National Kidney Foundation.Hyponatremia.Cobb M, Pacitti D.The importance of sodium restrictions in chronic kidney disease.J Ren Nutr. 2018;28(5):e37-e40. doi:10.1053/j.jrn.2018.02.001
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Sodium blood test.Wang YJ, Yeh TL, Shih MC, Tu YK, Chien KL.Dietary sodium intake and risk of cardiovascular disease: A systematic review and dose-response meta-analysis.Nutrients. 2020;12(10):2934. doi:10.3390/nu12102934Bernal A, Zafra MA, Simón MJ, Mahía J.Sodium homeostasis, a balance necessary for life.Nutrients. 2023;15(2):395. doi:10.3390/nu15020395UpToDate.Overview of the treatment of hyponatremia in adults.Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015;91(5):299-307.Hoorn EJ, Zietse R.Diagnosis and treatment of hyponatremia: compilation of the guidelines.J Am Soc Nephrol. 2017;28(5):1340-1349. doi:10.1681/ASN.2016101139Kim GH.Pathophysiology of drug-induced hyponatremia.J Clin Med. 2022;11(19):5810. doi:10.3390/jcm11195810Jomova K, Makova M, Alomar SY, et al.Essential metals in health and disease.Chem Biol Interact. 2022;367:110173. doi:10.1016/j.cbi.2022.110173Yun G, Baek SH, Kim S.Evaluation and management of hypernatremia in adults: clinical perspectives.Korean J Intern Med. 2023;38(3):290-302. doi:10.3904/kjim.2022.346National Kidney Foundation.Hyponatremia.Cobb M, Pacitti D.The importance of sodium restrictions in chronic kidney disease.J Ren Nutr. 2018;28(5):e37-e40. doi:10.1053/j.jrn.2018.02.001
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus.Sodium blood test.Wang YJ, Yeh TL, Shih MC, Tu YK, Chien KL.Dietary sodium intake and risk of cardiovascular disease: A systematic review and dose-response meta-analysis.Nutrients. 2020;12(10):2934. doi:10.3390/nu12102934Bernal A, Zafra MA, Simón MJ, Mahía J.Sodium homeostasis, a balance necessary for life.Nutrients. 2023;15(2):395. doi:10.3390/nu15020395UpToDate.Overview of the treatment of hyponatremia in adults.Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015;91(5):299-307.Hoorn EJ, Zietse R.Diagnosis and treatment of hyponatremia: compilation of the guidelines.J Am Soc Nephrol. 2017;28(5):1340-1349. doi:10.1681/ASN.2016101139Kim GH.Pathophysiology of drug-induced hyponatremia.J Clin Med. 2022;11(19):5810. doi:10.3390/jcm11195810Jomova K, Makova M, Alomar SY, et al.Essential metals in health and disease.Chem Biol Interact. 2022;367:110173. doi:10.1016/j.cbi.2022.110173Yun G, Baek SH, Kim S.Evaluation and management of hypernatremia in adults: clinical perspectives.Korean J Intern Med. 2023;38(3):290-302. doi:10.3904/kjim.2022.346National Kidney Foundation.Hyponatremia.Cobb M, Pacitti D.The importance of sodium restrictions in chronic kidney disease.J Ren Nutr. 2018;28(5):e37-e40. doi:10.1053/j.jrn.2018.02.001
MedlinePlus.Sodium blood test.
Wang YJ, Yeh TL, Shih MC, Tu YK, Chien KL.Dietary sodium intake and risk of cardiovascular disease: A systematic review and dose-response meta-analysis.Nutrients. 2020;12(10):2934. doi:10.3390/nu12102934
Bernal A, Zafra MA, Simón MJ, Mahía J.Sodium homeostasis, a balance necessary for life.Nutrients. 2023;15(2):395. doi:10.3390/nu15020395
UpToDate.Overview of the treatment of hyponatremia in adults.
Braun MM, Barstow CH, Pyzocha NJ.Diagnosis and management of sodium disorders: hyponatremia and hypernatremia.Am Fam Physician. 2015;91(5):299-307.
Hoorn EJ, Zietse R.Diagnosis and treatment of hyponatremia: compilation of the guidelines.J Am Soc Nephrol. 2017;28(5):1340-1349. doi:10.1681/ASN.2016101139
Kim GH.Pathophysiology of drug-induced hyponatremia.J Clin Med. 2022;11(19):5810. doi:10.3390/jcm11195810
Jomova K, Makova M, Alomar SY, et al.Essential metals in health and disease.Chem Biol Interact. 2022;367:110173. doi:10.1016/j.cbi.2022.110173
Yun G, Baek SH, Kim S.Evaluation and management of hypernatremia in adults: clinical perspectives.Korean J Intern Med. 2023;38(3):290-302. doi:10.3904/kjim.2022.346
National Kidney Foundation.Hyponatremia.
Cobb M, Pacitti D.The importance of sodium restrictions in chronic kidney disease.J Ren Nutr. 2018;28(5):e37-e40. doi:10.1053/j.jrn.2018.02.001
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