Serum sodium

Alternative names:

Na+; sodium - serum

What the risks are:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations:

Interfering factors:

• recent trauma, surgery, or shock
• ingestion of large or small amounts of salt or fluid
• intravenous fluids containing sodium

Drugs that can increase sodium measurements include anabolic steroids, antibiotics, clonidine, corticosteroids, cough medications, laxatives, methyldopa, nonsteroidal anti-inflammatory analgesics, and oral contraceptives.

Drugs that can decrease sodium measurements include carbamazepine, diuretics, sulfonylureas, triamterene, and vasopressin.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.