Cytomegalovirus (CMV) is a common virus. Once infected, your body retains the virus for life. Most people don’t know they have CMV because it rarely causes problems in healthy people.
A positive test for CMV IgG indicates that a person was infected with CMV at some time during their life but does not indicate when a person was infected.
In the United States, nearly one in three children are already infected with CMV by age five. Over half of adults have been infected with CMV by age 40. Once CMV is in a person’s body, it stays there for life and can reactivate. A person can also be re-infected with a different strain (variety) of the virus. Most people with CMV infection have no symptoms and aren’t aware that they have been infected.
In some cases, infection in healthy people can cause mild illness that may include:
- Sore throat
- Swollen glands
People with weakened immune systems who get CMV can have more serious symptoms affecting the eyes, lungs, liver, esophagus, stomach, and intestines.
When a baby is born with cytomegalovirus (CMV) infection, it is called congenital CMV. About one out of every 200 babies is born with congenital CMV infection. About one in five babies with congenital CMV infection will have long-term health problems.
Babies born with CMV can have brain, liver, spleen, lung, and growth problems. The most common long-term health problem in babies born with congenital CMV infection is hearing loss, which may be detected soon after birth or may develop later in childhood.
CMV is related to the viruses that cause chickenpox, herpes simplex and mononucleosis. CMV may cycle through periods when it lies dormant and then reactivates. If you’re healthy, CMV mainly stays dormant.
When the virus is active in your body, you can pass the virus to other people
- From direct contact with saliva or urine, especially from babies and young children
- Through sexual contact
- From breast milk to nursing infants
- Through transplanted organs and blood transfusions
If CMV testing indicates the donor has a current infection (positive CMV IgM), the donor is not eligible to participate in the program at that time. If, through periodic testing, it is determined that a donor has become infected, he will likewise be deferred and any retained vials since his last negative result will be discarded. If CMV testing indicates the donor only has an old infection (positive CMV IgG but negative CMV IgM), he will be accepted into the program and his donor profile will indicate CMV positive.
MV Total Antibody testing is performed on all donors prior to qualification and at approximate 90-day intervals thereafter. Negative results are consistent with no previous infection. If the Total Antibody test is positive, additional testing for CMV IgG Antibody and CMV IgM Antibody is performed to determine if the result represents a recent or old infection. A positive CMV IgM result is consistent with a current or recent CMV infection. A positive CMV IgG result in combination with a negative CMV IgM result indicates historic exposure to the CMV virus. These latter results are consistent with a normal immune response.