CMV antibody tests
The CMV serology test determines the presence of antibodies to a virus called cytomegalovirus (CMV) in the blood.
A blood sample is needed.
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. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
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.
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 a current or recent 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.
Veins and arteries vary in size from one person 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)
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.
Costello M, Sabatini LM, Yungbluth M. Viral infections. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 55.
Crumpacker CS. Cytomegalovirus. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 140.