Clinical significance
Rubella is a childhood rash illness that is normally self-limiting; however, when caught during pregnancy (especially in the first trimester), it can cause serious fetal malformations. In the Western world, the introduction of rubella vaccination has greatly reduced the number of people who are not immune and therefore at risk of infection.
During acute infection, specific class M antibodies (IgM) rise, followed by IgG, which remain for life.
Clinical indications
Suspected infection, checking that vaccination has taken, checking specific immunity at the start of pregnancy, surveillance for infection during pregnancy (in women not initially immune).
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed.
Notes
IgG absent, IgM absent: no exposure. If the clinical picture is uncertain, patients should be monitored over time.
IgG present, IgM absent: past infection.
IgG absent, IgM present: very early stage of infection.
IgG present, IgM present: acute or at least recent infection.