CMV serology test

Definition

The CMV serology test determines the presence of antibodies to cytomegalovirus (CMV) in the blood.

Alternative Names

CMV antibody tests

How the test is performed

A blood sample is needed. For information on how this is done, see: Venipuncture

Serology studies the fluid portion of blood (serum) for its antibody content. Serology tests are often repeated a few weeks after the first sample. There are several serology techniques that can be used, depending on the suspected antibodies.

How to prepare for the test

There is no special preparation for the test.

How the test will feel

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

Why the test is performed

The test is performed to detect current active CMV infection, or past CMV infection in people who are at risk for reactivation of infection (such as organ transplant recipients and people with a suppressed immune system). The test may also be performed to detect CMV infection in newborns.

Normal Values

People who have never been infected with CMV have no detectable antibodies to CMV.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

The presence of antibodies to CMV indicates a current or past infection with CMV. If the number of antibodies (called the antibody titer) rises over a few weeks, it may mean that you have an acute infection.

Chronic CMV infection (in which the antibody count stays about the same over time) can reactivate in a person with a suppressed immune system.

What the risks are

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample 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 lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Special considerations

To detect a blood or organ infection with CMV, the health care provider can test for the presence of CMV itself in the blood or a specific organ.

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References

Crumpacker CS II, Zhang JL. Cytomegalovirus. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 138.

Berger JR, Nath A. Cytomegalovirus, Epstein-Barr virus, and slow virus infections of the central nervous system In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 378.