Published on in CHOP News
All of Children's Hospital of Philadelphia’s (CHOP) COVID-19 testing sites for children will now be using a less invasive nasal swab, called anterior nares, to obtain the specimen for testing. CHOP operates drive-through and walk-in testing sites located across the Greater Philadelphia region. COVID-19 testing at these sites is free but is available by appointment only. Appointments can be made after a parent or guardian completes either an online or phone screening questionnaire to determine if a child needs a COVID-19 test. If the child meets criteria, the screening tool then provides options for making an appointment for a test.
PCR testing with different types of swabs
All of CHOP’s drive-through/walk-in testing sites use PCR testing. This is a molecular COVID-19 test that looks for and detects the RNA (or nucleic acid) component of the virus. “PCR” stands for “polymerase chain reaction” — a way of amplifying the RNA to make it more easily detected. Results of PCR tests are generally available within 24 to 48 hours.
Previously, a swab of a specimen was taken from the patient’s nose back near the throat (also known as nasopharyngeal). The testing sites are transitioning to swabbing only about 1 centimeter into each nostril for about 10 seconds each.
Are these test methods equally accurate?
The CHOP Infectious Disease Diagnostic Lab has conducted extensive testing to ensure that this less invasive method of performing a COVID-19 PCR test is as accurate and reliable as the previous method. We used the “back of the throat” swabbing until we had the data to confirm that the less invasive swab was as effective.
There may be specific circumstances where the “back of the throat” testing method is still recommended for certain patients, but the majority of children can now be reliably and accurately tested for COVID-19 using the less invasive swab.
For other tests diagnosed by PCR methods, such as tests for the flu and other viruses, “back of the throat” swabbing is still the primary method used for obtaining samples for diagnostic testing.
Rapid antigen testing at Urgent Care
Rapid antigen testing — with results available in 15 minutes — and PCR testing are available at CHOP’s four Urgent Care locations, which are open evenings and weekends. An Urgent Care visit is required, and therefore the family will be billed for the Urgent Care visit.
Antigen tests detect specific proteins from the virus, but these tests have a higher chance of missing an active infection. Rapid antigen testing is used when a child has symptoms or is seven days post an exposure, and an algorithm supports providers in choosing the most appropriate test for the child.
If the antigen test is negative but there is a very high suspicion that the child is COVID-positive, a PCR test will be performed.
Find all our COVID-19 resources for parents at chop.edu/covid.