CMV infection is a disease caused by a type of herpes virus. The CMV blood test is

performed to detect current active CMV infection, or past CMV infection in people who

are at risk for reactivation of infection. These people include organ transplant recipients

and those with a suppressed immune system.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. This applies for persons ≥12 months of age when maternal

antibodies are no longer present.