Proceeds from website advertising help sustain Lab Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services.


Print this article
Share this page:
Also known as: ALB
Formal name: Albumin, serum

Board approvedAll content on Lab Tests Online has been reviewed and approved by our Editorial Review Board.

The Test Sample

What is being tested?

Albumin is a protein made by the liver. It makes up about 60% of the total protein in the blood and plays many roles. This test measures the level of albumin in the blood.

Albumin keeps fluid from leaking out of blood vessels; nourishes tissues; and transports hormones, vitamins, drugs, and substances like calcium throughout the body. Levels of albumin may decrease, to a greater or lesser degree, when conditions interfere with its production by the liver, increase protein breakdown, increase protein loss via the kidneys, and/or expand plasma volume (diluting the blood).

Two important causes of low blood albumin include:

  • Severe liver disease—since albumin is produced by the liver, its level can decrease with loss of liver function; however, this typically occurs only when the liver has been severely affected.
  • Kidney disease—one of the many functions of the kidneys is to conserve plasma proteins such as albumin so that they are not released along with waste products when urine is produced. Albumin is present in high concentrations in the blood, and when the kidneys are functioning properly, virtually no albumin is lost in the urine. However, if a person's kidneys become damaged or diseased, they begin to lose their ability to conserve albumin and other proteins. This is frequently seen in chronic diseases, such as diabetes and hypertension. In nephrotic syndrome, very high amounts of albumin are lost through the kidneys.

For more information, read The Test tab.

How is the sample collected for testing?

A blood sample is taken by a needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.