Parvovirus B19 IgG and IgM Antibodies Blood Test

Parvovirus B19 IgM antibodies are produced during an active or recent infection with parvovirus B19, the virus that causes fifth disease (also called "slapped cheek syndrome" in children). These antibodies typically appear when symptoms begin and usually decline within two to three months after infection. The presence of IgM antibodies indicates current or recent infection, which is important to identify if you're pregnant as parvovirus can occasionally cause complications including miscarriage or anaemia in the baby. This test is interpreted alongside Parvovirus B19 IgG to determine whether the infection is acute or if you have immunity from a past infection.

Parvovirus B19 IgG antibodies develop a few weeks after infection and persist for life, indicating past infection and lasting immunity to the virus. Unlike IgM antibodies which signal recent infection, IgG antibodies show that you've been infected with parvovirus B19 before and now have protection against reinfection. This is particularly relevant during pregnancy - if you have IgG antibodies without IgM, it means you're already immune and parvovirus poses no risk to your baby. The presence of IgG alongside IgM, however, suggests a recent infection that requires monitoring, particularly in pregnant women.