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

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.

There is no special preparation needed.

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.

This test detects the body's response to RSV, not 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.

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.

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 maternal antibody, and therefore may not indicate true infection with RSV.

Risks associated with having blood drawn are mild:

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins

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.