RSV antibody test

Definition

RSV antibody test is a blood test that measures the levels of antibodies (immunoglobulins) against the viral infection respiratory syncytial virus (RSV).

Alternative Names

Respiratory syncytial virus antibody test; RSV serology

How the test is performed

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

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 detects the body's response to RSV, it does detect the virus itself. If the body has produced antibodies against RSV, then either a current or past infection has occurred.

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

Normal Values

In infants, a positive test may detect RSV antibodies that were passed from mother to child. In children, a positive test may indicate either current or past infection with RSV. Most adults will have a positive test because most people have 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.

What abnormal results mean

A positive test in age groups other than infants indicates a current or past infection with RSV. Because most adults have had an RSV infection, a positive test most likely reflects a past infection.

In infants a positive test most likely reflects antibodies transmitted from the mother, and therefore may not indicate a true RSV infection.

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 of limited value because it does not detect RSV directly. It is not recommended in infants because maternal antibodies may be detected, and it is not useful in adults as most people will have antibodies due to prior infection.