Definition of RSV antibody test:

RSV antibody test is a blood test that measures the levels of antibodies (immunoglobulins) that the body makes after an infection with the respiratory syncytial virus (RSV).

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture.

How to prepare for the test:

There is no special preparation needed.

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test is done to identify someone who has been infected by RSV recently or in the past.

This test detects the virus itself. If the body has produced antibodies against RSV, then either a current or past infection has occurred.

In infants, RSV antibodies that have been passed from mother to baby may also be detected.

Normal Values:

A negative test means the person does not have antibodies to RSV in the blood. This means the person has never had an RSV infection.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean:

A positive test means the person has antibodies to RSV in the blood. These antibodies may be present because:

• A positive test in people older than infants means there is a current or past infection with RSV. Most adults and older children have had an RSV infection.
• Infants may have a positive test because antibodies were passed from their mother to them before they were born. This may mean they have not had a true RSV infection.
• Some children younger than 24 months get a shot with antibodies to RSV to protect them. These children will also have a positive test.

What the risks are:

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Special considerations:

This test is not much help because it does not detect RSV directly. It is not recommended in infants because the mother's antibodies may be detected. It is not useful in adults because most people have antibodies due to a past infection.