Albumin Test, Blood
Albumin Test, Blood
Albumin is a type of protein found in the plasma (liquid) portion of the blood. Of all the types of protein in plasma, albumin is found in the highest concentrations, constituting about two-thirds of total plasma protein.
Albumin serves a number of important purposes. It transports a variety of other important chemicals in the blood, allowing them to be delivered to various organs and tissues. Chemicals that bind to albumin include thyroxine, bilirubin, penicillin, cortisol, estrogen, free fatty acids, warfarin, calcium, magnesium, and heme. Appropriate levels of albumin are also necessary in order to maintain sufficient quantities of fluid within the blood vessels. When the correct concentration of albumin is present in the blood’s serum, fluid remains in the blood vessels in order to reach a chemical equilibrium of protein concentrations in and outside of the blood vessels. When there is an insufficient amount of albumin in the serum, fluid will leak out of the blood vessels in response to the considerably higher concentration of protein in the surrounding tissues. This can result in visible swelling of the lower legs (referred to as edema), or in ascites (an abnormal collection of fluid in the abdomen).
Albumin levels are tested in order to monitor liver and kidney functioning, and in order to ascertain an individual’s nutritional status. Albumin levels may be checked if there is new edema or ascites. Albumin is manufactured in the liver, therefore, low albumin levels may indicate liver damage. Under normal circumstances, no albumin leaves the body in urine; however, when the kidneys are damaged, they may become leaky, allowing albumin to be excreted in the urine. This happens, for example, in nephrotic syndrome, and in pregnant women with preeclampsia and eclampsia. Individuals who have poor diets, with an extremely low dietary intake of protein, may also have low serum albumin.
An increased concentration of albumin may suggest that an individual has become dehydrated. High albumin levels may also occur when an individual is using insulin, growth hormones, androgens, or anabolic steroids.
Individuals who have been on intravenous fluids may not have an accurate serum albumin reading. Additionally, it’s important to remember that women have lower-than-normal serum albumin levels during pregnancy. Individuals using certain medications, such as insulin, growth hormones, androgens, or anabolic steroids, may also have an abnormal serum albumin level.
This test is usually performed as part of a panel of blood tests, in which a single sample of blood is tested for a variety of chemical elements. Serum albumin levels are often tested along with total protein levels. A blood test for serum albumin requires vein puncture with a needle, and is usually performed by a nurse of phlebotomist (an individual who has been trained to draw blood).
There are no restrictions on diet or physical activity, either before or after the blood test.
As with any blood tests, discomfort, bruising, and/or a very small amount of bleeding is common at the puncture site. Immediately after the needle is withdrawn, it is helpful to put pressure on the puncture site until the bleeding has stopped. This decrease
Ascites— An abnormal collection of fluid within the abdomen, often suggests liver disease such as cirrhosis.
Cirrhosis— Liver disease that results in damage and scarring to the liver.
Dehydration— Low overall levels of body fluid. May occur due to increased loss of fluids through sweating, vomiting, or diarrhea.
Eclampsia— A serious, life-threatening complication of pregnancy, in which high blood pressure results in a variety of problems, including seizures.
Nephrotic syndrome— A kidney disorder which causes a cluster of symptoms, including low serum protein, loss of protein in the urine, and body swelling.
Plasma— The fluid component of blood which contains such substances as proteins, vitamins, minerals, enzymes, and sugars.
Preeclampsia— High blood pressure in pregnancy, which can result in protein in the urine; untreated, preeclampsia may lead to the life-threatening condition known as eclampsia, which is characterized by seizures.
the chance of significant bruising. Warm packs may relieve minor discomfort. Some individuals may feel briefly woozy after a blood test, and they should be encouraged to lie down and rest until they feel better.
Basic blood tests, such as serum albumin levels, do not carry any significant risks, other than slight bruising and the chance of brief dizziness.
In general, the normal range of serum albumin is 3.4 to 5.4 g/dL (grams per deciliter). Different labs may have slightly different values listed for the normal range of serum albumin. If total serum proteins are also being tested, the fraction that is made up of albumin should be about 60%.
Low albumin may indicate:
- liver disease, such as cirrhosis, hepatitis, or hepato-cellular necrosis (death of liver cells);
- kidney disease, such as nephritic syndrome or glomerulonephritis;
- severe malnutrition, as occurs in developing countries where protein deficiencies are common. This type of malnutrition is referred to as kwashiorkor, and results in the stereotypical “potbelly” often associated with malnourished children;
- malnourishment due to chronic diseases such as HIV or cancer, or due to the effects of an eating disorder such as anorexia nervosa;
- inability to absorb and digest protein, as occurs in Crohn’s disease, Whipple’s disease, or sprue;
- loss of protein from severe or chronic diarrhea;
- severe burns; or
High albumin levels can result from dehydration or the presence of certain medications.
Brenner, B. M., and F. C. Rector, eds. Brenner & Rector’s The Kidney, 7th ed. Philadelphia: Saunders, 2004.
Feldman, M., L. S. Friedman, and L. J. Brandt. Sleisenger & Fordtran’s Gastrointestinal and Liver Disease, 8th ed. St. Louis: Mosby, 2006.
McPherson R. A., and M. R. Pincus, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods, 21st ed. Philadelphia: Saunders, 2006.
Medical Encyclopedia. Medline Plus. U. S. National Library of Science and the National Institutes of Health. http://www.nlm.nih.gov/medlineplus/encyclopedia.html (February 10, 2008).
American Association for Clinical Chemistry, 1850 K Street, NW, Suite 625, Washington, DC, 20006, (800) 892-1400, http://www.aacc.org.
Rosalyn Carson-DeWitt, M.D.
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