Total protein

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Blood test

This is a test that measures the total amount of protein in serum (serum is the fluid portion of blood, without fibrinogen).

TP

Blood is drawn from a vein or a capillary. The laboratory centrifuges the blood to separate the serum from the cells. The total protein test is done on serum.

Your health care provider may instruct you to withhold certain drugs that can affect the test.

Drugs that can increase total protein measurements include anabolic steroids, androgens, corticosteroids, dextran, growth hormone, insulin, phenazopyridine, and progesterone.

Drugs that can decrease total protein measurements include ammonium ions, estrogens, hepatotoxic drugs, and oral contraceptives.

Total protein is a rough measure of serum protein. Protein measurements can reflect nutritional state, kidney disease, liver disease, and many other conditions. If total protein is abnormal, further tests must be performed to identify which protein fraction, and then which specific protein, is abnormal.

Proteins are important constituents of all cells and tissues. Proteins are made from amino acids. There are many different kinds of proteins in the body with many different functions. Enzymes, some hormones, hemoglobin (oxygen transport), LDL (cholesterol transport), fibrinogen, (blood clotting), collagen (structure of bone and cartilage), immunoglobulins (antibodies ) are some examples of proteins.

Serum proteins are separated into two groups: albumin and globulins. Total protein equals albumin plus globulin. Globulins are roughly divided into alpha-1, alpha-2, beta, and gamma globulins.

Albumin is the protein of highest concentration in the serum (plasma is serum plus fibrinogen). Albumin is a carrier of many small molecules, but is also of prime importance in maintaining the osmotic pressure of the blood (that is, keeping the fluid from leaking out into the tissues).

Review Date: 06/01/2005
Reviewed By: Aniket R. Sidhaye, M.D., Division of Endocrinology and Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network.