Sodium (Na) in Blood

Blood Sodium

Results

A sodium test checks how much sodium (an electrolyte and a mineral) is in the blood. Normal values may vary from lab to lab. Results are ready in 1 day.

Sodium

Blood, Adult:	136–145 milliequivalents per liter (mEq/L) or 136–145 millimoles per liter (mmol/L)
Blood, Children:	138–145 milliequivalents per liter (mEq/L) or 138–145 millimoles per liter (mmol/L)

Many conditions can affect sodium levels. Your doctor will talk with you about any abnormal results that may be related to your symptoms and medical history.

High values

• High sodium levels (hypernatremia) can be caused by a high-sodium diet or by not drinking enough water and being dehydrated. Dehydration may also be caused by severe vomiting or diarrhea, Cushing's syndrome, kidney disease or injury, diabetic ketoacidosis, or a condition called diabetes insipidus that makes it hard to balance the water level in the body.
• High sodium levels can also be caused by high levels of the hormone aldosterone (hyperaldosteronism).

Low values

• Low sodium levels (hyponatremia) can be caused by a lot of sweating, burns, severe vomiting or diarrhea, drinking too much water (psychogenic polydipsia), or poor nutrition.
• Low sodium levels can also be caused by underactive adrenal glands or thyroid gland, heart failure, kidney disease, cirrhosis, cystic fibrosis, or SIADH (syndrome of inappropriate antidiuretic hormone secretion).

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Author:	Caroline Rea, RN, BS, MS	Last Updated: September 18, 2008
Medical Review:	E. Gregory Thompson, MD - Internal Medicine Avery L. Seifert, MD - Urology
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