Definition of Albumin - serum:

Albumin is a protein made by the liver. A serum albumin test measures the amount of this protein in the clear liquid portion of the blood.

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture. The blood sample is placed in a machine called a centrifuge, which spins and separates the cells from the liquid part of the blood (the serum).

How to prepare for the test:

The health care provider will tell you if you need to stop taking any drugs that may affect the test. Drugs that can increase albumin measurements include anabolic steroids, androgens, growth hormone, and insulin.

Why the test is performed:

This test can help determine if a patient has liver disease or kidney disease, or if the body is not absorbing enough protein.

Albumin helps move many small molecules through the blood, including bilirubin, calcium, progesterone, and medications. It plays an important role in keeping the fluid from the blood from leaking out into the tissues.

Because albumin is made by the liver, decreased serum albumin may be a sign of liver disease. It can also result from kidney disease, which allows albumin to escape into the urine. Decreased albumin may also be explained by malnutrition or a low protein diet.