Proteins are important parts of all cells and tissues. For example, albumin helps prevent fluid from leaking out of blood vessels. Globulins are an important part of your immune system.
How the test is performed
Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.
Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
The blood sample is placed into a machine called a centrifuge, which spins the blood to separate the the liquid part of the blood (the serum) from the cells. The total protein test is done on serum.
How to prepare for the test
Your health care provider may tell you to stop taking 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.
Why the test is performed
The normal range is 6.0 to 8.3 gm/dl (grams per deciliter).
Normal values may vary slightly from laboratory to laboratory.
What abnormal results mean
Higher-than-normal levels may be due to:
- Chronic inflammation or infection, including HIV and hepatitis B or C
- Multiple myeloma
- Waldenstrom's disease
Lower-than-normal levels may be due to:
- Bleeding (hemorrhage)
- Burns (extensive)
- Liver disease
- Nephrotic syndrome
- Protein-losing enteropathy
Additional conditions under which the test may be performed:
Total protein measurement may be increased during pregnancy.
Bazari H. Approach to the patient with renal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 115.
Klein S. Protein-energy malnutrition. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 234.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.