To determine if you have, or recently had, a parvovirus B19 infection, various tests may be employed.
Typically, a blood sample is drawn from a vein in your arm for parvovirus B19 antibody testing. To detect the virus itself, the sample tested may be blood or, rarely, bone marrow. In certain cases, fetal cord blood or amniotic fluid may be collected to test for fetal parvovirus B19 infection.
By doing antibody testing, if both parvovirus B19 IgG and IgM are present, then it is likely that the person tested has an active, or had a recent, parvovirus infection.
If there is a 4-fold increase in IgG between the first and second sample, then the person has an active, or had a recent infection.
If only IgM is present, then the person may have very recently been infected, within the previous 2-4 months.
If only parvovirus B19 IgG is present, then the person had a parvovirus infection at some time in the past and has protection against the virus.
If antibody tests are negative, then the person tested has not had the infection and is not immune.
If someone is symptomatic but has low or undetectable levels of IgG and/or IgM, it may mean that the person either has a condition other than parvovirus B19 or that their immune system is not responding normally.
By doing viral detection, if a parvovirus B19 DNA test is positive, then the person is currently infected with parvovirus B19.
A negative result does not rule out the infection. The virus may not be present in sufficient amount in the sample to be detected.
The PCR assay is used to detect viral DNA in immunocompromised patients as the antibody levels are variable.
Keywords: Parvo B19, Parvovirus, Parvovirus B19