Alternate Names : Serum Sodium, NA+, Lytes
This test measures the amount of sodium that is in the blood or
serum. Sodium is one of the main minerals called electrolytes that are found in
Who is a candidate for the test?
If a doctor suspects one of the conditions that results from too high or
too low a level of sodium, he or she may order this test.
How is the test performed?
In order to measure the amount of sodium in the blood, a blood
sample is taken from a vein on the forearm or hand. First, the skin over the vein
is cleaned with an antiseptic. Next, a rubber tube called a tourniquet is tied
around the upper arm. This enlarges the veins in the lower arm by restricting
blood flow through them. A fine needle is gently inserted into a vein, and the
tourniquet is removed. Blood flows from the vein through the needle and is
collected in a syringe or vial for testing in the laboratory. After the needle is
withdrawn, the puncture site is covered for a short time to prevent bleeding.