RSV antibody test

Definition

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

Alternative Names

Respiratory syncytial virus antibody test; RSV serology; Bronchiolitis - RSV test

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

No special preparation is needed.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.

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 does not 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 that have been passed from mother to baby may also be detected.

Normal Results

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

What Abnormal Results Mean

A positive test means the person has antibodies to RSV in their 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.

Risks

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person 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
• Multiple punctures to locate veins
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

References

Crowe JE. Respiratory syncytial virus. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 260.

Mazur LJ, Costello M. Viral infections. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 56.