What is a sodium
A sodium blood test is a routine test that allows your
doctor to see how much sodium is in your blood. It’s also called a serum sodium
test. Sodium is an essential mineral to your body. It’s also
referred to as Na+.
Sodium is particularly important for nerve and muscle
function. Your body keeps sodium in balance through a variety of mechanisms.
Sodium gets into your blood through food and drink. It leaves the blood through
urine, stool, and sweat. Having the right amount of sodium is important for
your health. Too much sodium can raise your blood pressure.
A lack of sodium can cause symptoms such as:
When do you receive
a sodium blood test?
The sodium blood test is often part of a basic metabolic
panel. This is a group of related tests. The basic metabolic panel includes
- blood urea nitrogen
Blood sodium can also be part of an electrolyte panel.
Electrolytes are substances that carry an electrical charge. Potassium and
chloride are other electrolytes.
This test may be ordered if you have:
- eaten large amounts of salt
- not eaten enough or had enough
- a serious illness, or gone
- received intravenous fluids
You may also receive this test to monitor medications that
affect your sodium levels. These include diuretics and certain hormones.
is the sodium blood test done?
This test is performed on a blood sample, obtained by
venipuncture. A technician will insert a small needle into a vein on your arm
or hand. This will be used to fill a test tube with blood.
do I prepare for the sodium blood test?
You don’t need to prepare for this test. Consume a normal
amount of food and water before going to the testing site. You may have to stop
taking certain medications before this test. But, drugs should only be stopped
on a doctor’s instruction.
are the risks of the sodium blood test?
When the blood is collected, you may feel some moderate pain
or a mild pinching sensation. Any discomfort should only last a short time.
After the needle is taken out, you may feel a throbbing sensation. You’ll be
instructed to apply pressure to the puncture. A bandage will be applied.
There are few risks to taking a blood sample. Rare problems
- lightheadedness or fainting
- a bruise near the area the
needle was inserted, also known as hematoma
- excessive bleeding
If you bleed for a long period after your test, it may
indicate a more serious condition. Excessive bleeding should be reported to
the results of a sodium blood test
Your doctor will go over your results with you. Results
range from normal to abnormal.
Normal results for this test are 135 to 145 mEq/L (milliequivalents
per liter), according to the Mayo Clinic. But different laboratories use
different values for “normal.”
A blood sodium level lower than 135 mEq/L is called
hyponatremia. Symptoms of hyponatremia include:
- nausea and vomiting
- loss of appetite
- confusion or disorientation
- loss of consciousness or coma
Hyponatremia can cause damage to cells. It makes them swell
up with too much water. This may be particularly dangerous in areas such as the
Hyponatremia is more often a problem in older adults. It can
be caused by:
- certain pain medications
- large burns on the skin
- kidney disease
- liver disease or cirrhosis
- severe diarrhea or vomiting
- heart failure
- high levels of certain
hormones, such as antidiuretic hormone or vasopressin
- drinking too much water
- not urinating enough
- excessive sweating
- ketones in the blood, known
- underactive thyroid, or hypothyroidism
- Addison’s disease, which is
low hormone production in the adrenal gland
Abnormally high levels
Hypernatremia means high levels of sodium in the blood. It’s
defined as levels that exceed 145 mEq/L. Symptoms of hypernatremia include:
- swelling in hands and feet
- rapid heartbeat
Hypernatremia is most often a problem in older adults,
infants, and people who are bedridden. Causes of hypernatremia include:
- not drinking enough water
- drinking salty water
- eating too much salt
- excessive sweating
- low levels of hormones such
- high levels of aldosterone
- Cushing’s syndrome, caused by
Certain medications can also potentially cause hypernatremia. These include:
- birth control pills
anti-inflammatory pain medications
blood sodium test is ordered by your doctor for a number of reasons. Sometimes
it’s needed because you may be on certain medications that affect the sodium
levels in your blood. Other times it may be part of a general health checkup.
Either way it’s important to know how much sodium in your blood. Keeping it at
the optimum level is good for your overall health.