Rubeola Antibody (Blood)
Does this test have other names?
Test for measles-specific IgM antibody
What is this test?
This test looks for an antibody called measles-specific IgM in your blood. If you
have been exposed to the rubeola virus, your body may have made this antibody. The
rubeola virus causes measles, an extremely contagious disease. It is spread through
the air in droplets after people cough or sneeze.
Thirty percent of people who catch the measles have complications. These include pneumonia,
diarrhea, and ear infections that may cause permanent hearing loss. In rare cases,
children may get encephalitis. This is a brain infection that can cause intellectual
disability and deafness.
Measles is much less common than in the past because so many children in the U.S.
are now vaccinated against the disease. Most cases in the U.S. are among people who
have brought the disease from other countries and spread it to others who are unvaccinated.
Why do I need this test?
You may need this test if you have been exposed to measles and have not been vaccinated
against the disease. If you are infected with the measles virus, you may not develop
symptoms for 2 weeks.
You may also need this test if you have symptoms of measles. These include:
What other tests might I have along with this test?
Your healthcare provider may also order tests for mumps or German measles (rubella).
What do my test results mean?
Test results may vary depending on your age, gender, health history, the method used
for the test, and other things. Your test results may not mean you have a problem.
Ask your healthcare provider what your test results mean for you.
Normal results are negative, meaning you don't have the measles-specific IgM antibody
in your blood. A positive result means the antibodies have been found and it's likely
you have a measles infection.
Levels of measles-specific IgM antibody in your blood will rise shortly after the
rash becomes visible. It may be necessary to repeat the test several days after the
rash begins. This should be done in case at the time of the initial test the antibodies
were not high enough to detect in the blood.
What might affect my test results?
Timing is important for this test. Your body may not create much IgM antibody at the
beginning of the infection, which would give a false-negative result. You may need
to have the test again after the rash has been visible for several days. If you've
recently been vaccinated against the measles, your IgM antibody level might be higher,
giving a false-positive.
How is this test done?
The test is done with a blood sample. A needle is used to draw blood from a vein in
your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection,
bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may
feel a slight sting or pain. Afterward, the site may be sore.
How do I get ready for this test?
You don't need to prepare for this test. Be sure your healthcare provider knows about
all medicines, herbs, vitamins, and supplements you are taking. This includes medicines
that don't need a prescription and any illicit drugs you may use.