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The Test Sample
What is being tested?
Respiratory syncytial virus (RSV) is a very contagious, common viral respiratory infection. RSV testing detects the presence of respiratory syncytial virus in nasal secretions to help diagnose the infection.
Most people recover from an RSV infection without any specific treatment or having to see a healthcare practitioner to get tested. However, testing may be done for infants, young children with heart or lung problems, the elderly, and people with weakened immune systems because they are particularly vulnerable. In these high-risk groups, RSV can cause pneumonia and bronchiolitis, a condition that causes inflammation of the small airways of the lungs.
Signs and symptoms of RSV infection are similar to those of other respiratory infections and usually appear 4 to 6 days after someone comes into contact with the virus. Signs and symptoms may include:
- Runny nose
- Coughing, sneezing
- Reduced appetite
- In very young infants, the only symptoms may be irritability, sluggishness (inactivity), and difficulty breathing
According to the Centers for Disease Control and Prevention (CDC), almost everyone has been infected with RSV by the time they are 2 years old. It is the most common cause of lower respiratory tract infections in young children in the U.S. and globally.
Though usually causing a mild illness, RSV can be serious in some children and adults. Each year in the U.S., RSV leads to about:
- 2.1 million outpatient visits and 57,000 hospitalizations among children younger than 5 years old
- 177,000 hospitalizations and 14,000 deaths among adults older than 65 years
The World Health Organization (WHO) estimates that globally there may be as many as 30 million RSV lower respiratory infections in children younger than 5 years old, resulting in than 3.4 million hospitalizations each year.
RSV that tends to be seasonal, causing community epidemics in the fall, winter, and spring. Outbreaks typically begin to occur in November or December and decrease by early spring.
How is the sample collected for testing?
Sample collection technique is critical in RSV testing. The best and most frequently used sample is a nasal aspirate or wash. A syringe is used to push a small amount of sterile saline into the nose, then gentle suction is applied (for the aspirate) or the resulting fluid is collected into a cup (for a wash).
Sometimes, a nasopharyngeal (NP) swab is used, although it is not preferred because the amount of virus obtained on a swab is usually low. The NP swab is collected by having a person tip his or her head back, then a Dacron swab (like a long Q-tip) is gently inserted into one of the nostrils until resistance is met (about 1 to 2 inches in), then rotated several times and withdrawn. This is not painful, but it may tickle a bit and cause the person's eyes to tear.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.