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Testing and Diagnosis of CMV Infection

A person who has been infected with cytomegalovirus (CMV) will develop antibodies (proteins that indicate prior infection) to the virus that will stay in the body for the rest of that person’s life. A blood test for these antibodies can tell whether a person has ever been infected with CMV. Tests that can indicate when a person was infected are not widely available commercially. Tests that detect the virus are used to determine if a person has an active CMV infection. If the virus is detected in the blood, saliva, urine or other body tissues, it means that the person has an active infection.

CMV Testing during Pregnancy

Healthy pregnant women are not at special risk for disease from CMV infection. When infected with CMV, most women have no symptoms, but some may have symptoms resembling mononucleosis. Women who develop a mononucleosis or flu-like illness during pregnancy should consult their medical provider about CMV testing. See Information for Pregnant Women.

CDC does not recommend routine maternal screening for CMV infection during pregnancy. A single test cannot definitively rule out primary CMV infection during pregnancy, especially if testing occurs after the first trimester. Women who are concerned about CMV infection during pregnancy should consult their physicians about the best ways to avoid problems from CMV infection.

CMV Testing of Infants

Tests that detect the virus are used to diagnosis CMV infection at birth (congenital CMV infection). A diagnosis of congenital CMV infection can be made if the virus is found in an infant’s urine, saliva, blood, or other body tissues within 2-3 weeks after birth. Antibody tests cannot be used to diagnose congenital CMV; a diagnosis can only be made if the virus is detected within 2-3 weeks of life. Congenital CMV cannot be diagnosed if the infant is tested more than 2-3 weeks after birth. For details, see Interpretation of Laboratory Tests for CMV Infection.

Healthy infants are not routinely tested for CMV infection. If you find out that you became infected with CMV for the first time during your pregnancy, make sure your infant is tested for CMV as soon as he or she is born.

If your infant is diagnosed with congenital CMV infection, you should have his or her hearing and vision checked regularly.

Babies infected with CMV after birth generally are not at risk for problems unless they were born very prematurely and have very low birth weights.

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