Does Your Child Need an RSV Test?

A lot has changed since this Kansas City RSV outbreak back in 2013.
A lot has changed since this Kansas City RSV outbreak back in 2013.

Your toddler has a cough and runny nose and there is a notice that RSV is going around at daycare…

Do you need to rush to your pediatrician?

Does your child need an RSV test?

Like many things, it depends on who you ask.

For example, the folks at your child’s daycare might push for a visit and an RSV test, thinking it will help them keep the virus from spreading to other kids.

It won’t.

Does Your Child Need an RSV Test?

If an RSV test is available, why not do it?

“Our study showed that a simple nasal swab, while less painful for infants than NPA, failed to detect about one third of cases that were RSV positive by nasopharyngeal aspirate.”

Macfarlane et al on RSV testing in bronchiolitis: which nasal sampling method is best?

For one thing, the test isn’t that accurate, especially when done with a nasal swab, the most commonly used method. And while less invasive than a nasopharyngeal aspirate, if done correctly, sticking a nasal swab up your child’s nose, rotating it around a few times, and then getting a sample isn’t exactly something kids enjoy.

Mostly though, since there is no treatment for RSV, what are you going to do with those test results, whether or not they are positive?

Remember, RSV is a very common respiratory virus that can cause a cold, bronchiolitis, or pneumonia. But testing positive for RSV doesn’t mean that your child has bronchiolitis or pneumonia. Those are typically diagnosed clinically, based on the signs and symptoms that your child has, such as wheezing and trouble breathing.

Similarly, testing negative for RSV doesn’t mean that your child doesn’t have bronchiolitis or pneumonia.

“Clinicians should diagnose bronchiolitis and assess disease severity on the basis of history and physical exam.

When clinicians diagnose bronchiolitis on the basis of history and physical examination, radiographic or laboratory studies should not be obtained routinely.”

AAP on the Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis

Is there ever a role for RSV testing?

RSV testing might be a good idea when an infant has apnea or other uncommon symptoms.

And if a child is getting monthly Synagis injections and has a suspected case of RSV, it is a good idea to confirm that they actually have RSV.

Why?

If they really do, then you can stop getting Synagis injections, as they are unlikely to get RSV again in the same season.

“In the event an infant receiving monthly prophylaxis is hospitalized with bronchiolitis, testing should performed to determine if RSV is the etiologic agent. If a breakthrough RSV infection is determined to be present based on antigen detection or other assay, monthly palivizumab prophylaxis should be discontinued because of the very low likelihood of a second RSV infection in the same year. Apart from this setting, routine virologic testing is not recommended.”

AAP on the Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis

That’s pretty clear.

The American Academy of Pediatrics guidelines say that routine RSV testing is not recommended.

Need another good reason to avoid routine RSV testing?

Do you know how long kids with RSV shed the virus or can test positive after having an RSV infection?

“People infected with RSV are usually contagious for 3 to 8 days. However, some infants, and people with weakened immune systems, can continue to spread the virus even after they stop showing symptoms, for as long as 4 weeks.”

CDC on RSV Transmission

Apparently, it is a long time, which means that your child might have a new respiratory infection, but still test positive for RSV because they had it a month ago.

You might actually be “diagnosing” an old infection and not the virus that is causing your child’s current symptoms.

Do you still want an RSV test anyway? Talk to your pediatrician.

Did someone order an RSV test, but you are now wondering if it was necessary? Talk to your pediatrician.

Remember that an RSV test won’t change your child’s treatment (breathing treatments and steroids are no longer routinely recommended when infants have RSV), won’t help predict how sick your child might get, and won’t tell you if your child can return to daycare.

What To Know About RSV Tests

You likely won’t be able to avoid RSV season, especially if your kids are in daycare, but you can avoid RSV testing season.

More on RSV Tests

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