A person who has been infected with CMV will develop antibodies in their blood that indicate infection has occurred, either recently, or in the past. These antibodies stay in the body for the rest of that person’s life. Other tests, that detect the virus, are used to determine if a person has an active CMV infection.

Testing for CMV is not routinely recommended for all women during pregnancy or for newborn babies. CMV testing is currently recommended for pregnant women who develop an acute viral illness or when ultrasound reveals a foetal abnormality. However, pregnant women and women planning a pregnancy may wish to discuss CMV testing with their doctor, particularly if they work in high risk settings (e.g. in child care centres) or have very young children at home.

Infants born to mothers diagnosed with a primary CMV infection during pregnancy should be tested for congenital CMV infection. Babies who do not have a normal hearing screening test at birth (SWISH) can also be tested for congenital CMV, as hearing loss is the most common sign of congenital CMV. However, some infants with congenital CMV infection who appear healthy at birth develop hearing or vision loss over time; for this reason, babies known to be infected should have their hearing and vision assessed regularly.