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Protein electrophoresis - serum

Definition

This test measures the types of protein in the fluid (serum) part of a blood sample.

See also:

• Immunoelectrophoresis - serum
• Immunofixation - serum
• Serum globulin electrophoresis

Alternative Names

Lipoprotein electrophoresis

How the test is performed

A blood sample is needed. For information on giving a blood sample from a vein, see venipuncture.

Electrophoresis is a laboratory technique. The blood serum (the liquid part of the blood without the cells) is placed on specially treated paper and exposed to an electric current. The proteins in the serum move on the paper to form bands that show the proportion of each protein fraction. A fraction may contain several different types of proteins.

Individual proteins, except albumin, are not usually measured. However, protein fractions or groups ARE measured. The levels of protein fractions can be estimated by measuring the total serum protein and then multiplying that by the relative percentage of each protein fraction.

Lipoprotein electrophoresis is a type of protein electrophoresis that determines the amount of proteins made up of protein and fat, called lipoproteins (such as LDL cholesterol).

How to prepare for the test

You may be asked not to eat or drink for 12 hours before a lipoprotein electrophoresis test.

Your health care provider may ask you to stop taking drugs that could affect the test. Do not stop taking any medications without first talking to your health care provider.

Drugs that can affect the measurement of total proteins include chlorpromazine, corticosteroids, isoniazid, neomycin, phenacemide, salicylates, sulfonamides, and tolbutamide.

How the test will feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

Proteins are made from amino acids and are important components of all cells and tissues. There are many different kinds of proteins in the body with many different functions. Examples of proteins include enzymes, certain hormones, hemoglobin, low-density lipoprotein ("bad" cholesterol), and others.

Serum proteins are classified as albumin or globulins. Albumin is the protein of highest concentration in the serum. It carries many small molecules, but is also important for keeping fluid from leaking out from the blood vessels into the tissues.

Globulins are divided into alpha-1, alpha-2, beta, and gamma globulins. In general, alpha and gamma globulin protein levels increase when there is inflammation in the body.

Normal Values

• Total protein: 6.4 to 8.3 g/dL
• Albumin: 3.5 to 5.0 g/dL
• Alpha-1 globulin: 0.1 to 0.3 g/dL
• Alpha-2 globulin: 0.6 to 1.0 g/dL
• Beta globulin: 0.7 to 1.2 g/dL
• Gamma globulin: 0.7 to 1.6 g/dL

Note: g/dL = grams per deciliter

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Decreased total protein may indicate:

• Cirrhosis
• Malnutrition
• Nephrotic syndrome
• Gastrointestinal protein-losing enteropathy

Increased alpha-1 globulin proteins may be due to:

• Acute inflammatory disease
• Cancer
• Chronic inflammatory disease (for example, rheumatoid arthritis, SLE)

Decreased alpha-1 globulin proteins may be a sign of:

• Alpha-1 antitrypsin deficiency

Increased alpha-2 globulin proteins may indicate:

• Acute inflammation
• Chronic inflammation

Decreased alpha-2 globulin proteins may indicate:

• Hemolysis

Increased beta globulin proteins may indicate:

• Hyperlipoproteinemia (for example, familial hypercholesterolemia)
• Estrogen therapy

Decreased beta globulin proteins may indicate:

• Congenital coagulation disorder
• Consumptive coagulopathy
• Disseminated intravascular coagulation

Increased gamma globulin proteins may indicate:

• Multiple myeloma
• Chronic inflammatory disease (e.g., rheumatoid arthritis, SLE)
• Hyperimmunization
• Acute infection
• Waldenstrom's macroglobulinemia
• Chronic liver disease

Note: Blood test results may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What the risks are

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

References

McPherson R. Specific proteins. In: McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders; 2006:chap 19.