Sodium and potassium are important electrolytes. If you have abnormally high or low levels of these minerals in your blood, it can cause serious health problems. A blood test can show if you have normal sodium and potassium blood levels.
Sodium and potassium are two electrolytes — minerals with an electric charge — that are required for the proper functioning of your cells. Your health care provider can do a test to check that you have normal sodium and potassium blood levels.
Read more: Foods Containing Electrolytes
Testing for Sodium and Potassium Blood Levels
Blood sodium and potassium levels are often checked as part of a basic metabolic panel or an electrolyte panel, along with other electrolytes, such as chloride and bicarbonate. A health care provider will take a blood sample from a vein in your arm. Typically, no special preparation is required before the test. Your health care provider will inform you if you need to temporarily stop taking any medications that could affect the results.
Your health care provider may order sodium and potassium blood tests as part of your regular checkup, to monitor an existing condition that affects electrolytes or if you have symptoms of abnormal potassium or sodium levels.
Low Sodium: Hyponatremia
In most cases of hyponatremia, "you have excess water in your body that has diluted the concentration of sodium," Dr. Weiner says. Hyponatremia may be caused by a range of conditions, including heart failure, kidney disease, adrenal problems, cirrhosis of the liver, and syndrome of inappropriate anti-diuretic hormone (SIADH), in which your body retains water instead of excreting it normally in your urine.cause:
- Hyponatremia may be caused by a range of conditions
- including heart failure
- kidney disease
- adrenal problems
- cirrhosis of the liver,
- syndrome of inappropriate anti-diuretic hormone (SIADH)
- in which your body retains water instead of excreting it normally in your urine
It can also be a side effect of certain medications, like diuretics and antidepressants.
High Sodium: Hypernatremia
An elevated blood sodium level is called hypernatremia.
Just as hyponatremia is usually the result of too much water, "if you have high sodium, then you are dehydrated — you have too little water," says Dr. Weiner. That may be due to lack of access to water or because the urge or ability to drink is impaired 6. In rare cases, it may be caused by excessive intake of salt.
Symptoms of an abnormally high blood sodium level include excessive thirst, urinating frequently, vomiting and diarrhea.
Low Potassium: Hypokalemia
According to the Mayo Clinic, hypokalemia is most commonly the result of losing too much potassium in the urine due to the use of diuretic medications that increase urination 23. It may also be caused by kidney disease, eating disorders, alcoholism, certain hormonal or genetic disorders or the loss of bodily fluids from diarrhea, vomiting and sweating.cause:
- It may also be caused by kidney disease
- eating disorders
- certain hormonal or genetic disorders or the loss of bodily fluids from diarrhea
Laxatives and certain antibiotics may also cause low potassium levels.
High Potassium: Hyperkalemia
Hyperkalemia is most commonly caused by a problem with the kidneys. If the kidneys aren't able to remove the proper amount of potassium, it can build up in the blood. High potassium levels can also result from conditions including Addison's disease, type-1 diabetes, certain genetic disorders and burns or other traumatic injuries. It can also be a side effect of certain diuretics, antibiotics and blood pressure lowering drugs.
According to the Mayo Clinic, a potassium blood test will often come back with a falsely high level because the blood cells in the blood sample ruptured 23. A repeat test will be done if this suspected.
Read more: Symptoms of Potassium Overdose
It can also be due to fluid loss due to excessive sweating, vomiting, or diarrhea, or an underlying condition, including kidney disease, adrenal gland problems or diabetes insipidus. Hyponatremia may be caused by a range of conditions, including heart failure, kidney disease, adrenal problems, cirrhosis of the liver, and syndrome of inappropriate anti-diuretic hormone (SIADH), in which your body retains water instead of excreting it normally in your urine. Symptoms of low sodium levels include fatigue, confusion, muscle weakness and twitching, nausea and vomiting, headache.
- U.S. National Library of Medicine: "Sodium Blood Test"
- Mayo Clinic: "High Potassium (Hyperkalemia)"
- Mayo Clinic: "Low Potassium (Hypokalemia)"
- U.S. National Library of Medicine: "Potassium Blood Test"
- U.S. National Library of Medicine: "Low Potassium Level"
- UptoDate: "Etiology and Evaluation of Hypernatremia in Adults"
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