Two different types of rubella tests can be employed to detect the rubella virus: a virus culture or a blood test. The virus culture uses a small tissue sample which is placed in a container and allowed to regenerate over a period of several weeks. Doctors then study the cell growth to determine the presence of a virus. This test is rarely used because of the length of time needed. The more common of the rubella tests is a blood test or enzyme-linked immunosorbent assay, known as ELISA or EIA.
Blood tests can detect two different antibodies in the bloodstream that are used by the immune system to fight the rubella virus. There are two rubella tests in this category. The first, known as an IgG, detects the presence of the IgG antibody in the bloodstream; if found, it indicates an immunity to the virus, either due to a vaccination or a past infection. The second of these rubella tests, known as an IgM, detects the presence of IgM antibodies in the bloodstream. If these antibodies are present, it indicates a current or recent rubella infection.
Rubella, also known as German measles or three-day measles, often appears as a fever and rash. While not dangerous to most populations, it is contagious. Other symptoms can vary widely, making rubella tests the best way to accurately determine if the virus is present.
The rubella virus more seriously affects women of childbearing age. Pregnant women who are infected might transmit the virus to the fetus, which can result in birth defects ranging from cataracts and hearing impairment to heart defects and central nervous system disease. This is known as congenital rubella syndrome (CRS) and can lead to miscarriages or stillbirths. For this reason it is important for pregnant women, or women who wish to become pregnant, to undergo the rubella tests. There is no treatment for rubella other than the use of fever reducers such as acetaminophen, but defects that occur due to CRS can be treated.
If a newborn is suspected of having the rubella virus, a doctor may order both IgG and IgM rubella tests. These tests will be repeated two to three weeks later as new antibodies form in the newborn’s blood. Anyone diagnosed as not having the IgG antibody can choose to be vaccinated to avoid infection. Pregnant women, however, should not have the vaccination and should avoid exposure to anyone who might be infected with the rubella virus.