Rubella

Does this test have other names?

German measles, rubella antibody test, three-day measles

What is this test?

This test measures the amount of rubella antibodies in your blood to see if you have immunity against the rubella virus.

Rubella, also called the German measles, is a very contagious disease that's easily spread through coughing, sneezing, and spitting. In young children, rubella is usually a mild disease with symptoms that include sore throat and fever. Adults may have pink eye, headache, and discomfort up to five days before a rash appears.

It's important to know whether you have antibodies against rubella, especially if you're pregnant or know that you have been exposed to the virus. Getting rubella when you're pregnant can be especially dangerous for your fetus. A rubella infection can cause miscarriage or a stillborn infant. It can also cause many serious birth defects, which are more likely if the infection occurs in the first 16 weeks of pregnancy. These include heart defects, mental retardation, liver problems, deafness, blood disorders, and cataracts. Infants may later develop delayed motor skills, behavioral disorders, autism, immune disorders, thyroid problems, diabetes, and digestive disorders.

Once you've had rubella, you may develop a natural immunity so you won't get it again. If you're not immune or never had rubella, you can get vaccinated.

Why do I need this test?

If you are pregnant, you will have this test as part of your routine prenatal exams.

If you aren't immune to rubella, you can be vaccinated against the infection, but the shot is not recommended for women who are already pregnant. Women should not get pregnant for at least a month after having a rubella vaccine.

What other tests might I have along with this test?

If you are pregnant, your doctor may order a series of tests to evaluate your overall health. Your health care provider may also check for:

• Blood type (A, B, AB, or O)

• Rh factor (Rh positive or negative)

• Glucose

• Iron and hemoglobin levels

• Sexually transmitted diseases

• Toxoplasmosis

• Inherited diseases, such as hypercholesterolemia, cystic fibrosis, sickle-cell anemia, thalassemia, and Tay-Sachs disease

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.

Normal results are positive, meaning that you have enough antibodies to provide immunity against the rubella virus. Negative results mean that you don't have enough antibodies.

If you have rheumatoid arthritis or mononucleosis, you may have a false-positive result. If your immune system does not work the way it should, this test may give inaccurate results.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

When a blood sample is taken from a baby, it is usually drawn from the heel or, in a newborn, from the umbilical cord.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my test results?

If you've been treated for an immune system disorder or had a transfusion, you may get a false-positive result. People who have been exposed to parvovirus may also get false-positive results.

How do I get ready for the test?

You don't need to prepare for this test.