Respiratory syncytial virus (RSV) testing is usually used during the RSV season to help diagnose the infection in people who have moderate to severe symptoms and lower respiratory tract involvement. It is primarily ordered on infants (between the ages of 6 months and 2 years), the elderly, and those with compromised immune systems, such as those who have pre-existing lung disease or who have had an organ transplant. Older children and the rest of the general population are not routinely diagnosed or tested because most of them will experience only relatively mild upper respiratory infections with symptoms such as a runny nose, sneezing, coughing, sore throat, and fever.
RSV testing is also used to document and track the spread of RSV in the community. Since most cases of RSV are self-limiting, community health efforts are focused on containing and preventing the spread of RSV as much as possible to minimize the chance of spreading the virus to high-risk people. Treatment of RSV is primarily supportive, minimizing pain and fever and easing breathing. Those with mild symptoms may only be tested for RSV if it is necessary to help track its spread. RSV testing is frequently ordered along with influenza testing if both viruses are known to be present in the community. These tests are used to detect the presence of RSV or influenza and to evaluate the likelihood that an individual person's symptoms may be due to one of these viruses or to another cause, such as a bacterial infection.
Viral cultures or genetic respiratory virus testing may sometimes be used to help track RSV outbreaks and to identify other viral infections that may cause clinical symptoms similar to RSV.
RSV tests are ordered almost exclusively during "cold and flu season" – late fall to early spring. They are ordered when someone, usually an infant or elderly person, presents with a lower respiratory infection and symptoms such as:
Rapid breathing (primarily in infants)
Runny, stuffy nose
When RSV has already been identified in the community, the doctor may order a rapid RSV test to confirm the suspected diagnosis in the symptomatic person. If influenza is also in the community, RSV testing may be ordered along with influenza testing to determine which virus the person has. The doctor may also order bacterial tests, such as a strep test (to check for group A streptococcus, the bacteria that cause strep throat), when the cause of the infection is unclear.
If a rapid RSV test is positive, then it is likely that the person has a respiratory syncytial virus infection. A positive viral culture or genetic viral test can confirm the presence of RSV in the community. A positive RSV test cannot, however, tell a doctor how severe a person's symptoms are likely to be or how long ago they were infected. Symptoms usually appear 4-6 days after infection.
Negative rapid RSV tests may mean that the person tested has something other than RSV or that there is not sufficient virus in the specimen to allow it to be detected. This may be due to either a poor specimen collection or because the person is not shedding detectable levels of virus into his respiratory secretions. Adults tend to shed less virus than infants do, and those who have had RSV for several days will shed less than those with a more recent infection.
Most RSV infections will go away within 1 or 2 weeks. People can be re-infected with different strains of RSV from year to year, although subsequent infections tend to be less severe than the first/primary infection. Since most RSV infections are mild, symptoms from these re-infections are usually attributed to "a cold." These cases of RSV are usually not formally diagnosed and are often self-treated by the person with over-the-counter cold remedies for symptom relief.
This article was last reviewed on February 22, 2012. | This article was last modified on May 7, 2013.
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