Let’s Talk About COVID Testing

I often tell parents that I wish everything in pediatrics could be as easy as strep throat.  When a patient has symptoms, they can get a test that is fairly accurate with results returning in 5-10 minutes.  If their test is positive, we have antibiotics that can be prescribed, and typically the patient feels better within a day or two.  Unfortunately, with many infections including COVID-19, it isn’t that easy.  There are many questions around COVID-19 and testing, including who needs to be tested, when they should be tested, and what type of test should be used.

The Minnesota Department of Health (MDH) has created a decision tree to guide our decisions around testing.  If a patient has one of the “more common” COVID-19 symptoms (including fever, cough, shortness of breath) OR two or more of the “less common” COVID-19 symptoms (see link) then they are considered at risk for COVID-19 infection.  Prior to returning to the school or childcare setting, the patient can:

• Self-isolate for 10 days
• Be evaluated and provided an alternative diagnosis (for example strep throat or influenza)
• Have a negative COVID-19 test (along with improving symptoms)

This is the algorithm that most school and childcare settings in MN are currently using (including St David’s Center).  This means that many children with typical upper respiratory virus or common cold symptoms are going to have COVID-19 testing performed this fall and winter!

It is always a good idea to reach out to your child’s health care provider to discuss testing options. Most clinics are able to perform COVID-19 testing. Alternatively, MDH has a link on their website to the testing centers in Minnesota: https://mn.gov/covid19/for-minnesotans/if-sick/testing-locations/index.jsp. Note that some of these locations have age restrictions or may require a visit by telehealth with a provider prior to testing.

How the COVID test works

When a patient is tested for possible COVID-19 infection, the test may look for the virus or viral protein (PCR or antigen) or for antibodies that are produced by the body in response to viral infection (serology). The PCR test, which is considered the “gold standard,” looks for pieces of the SARS-CoV-2 virus in the respiratory tract. The nasopharyngeal swab (deep nasal swab) is able to detect virus that may be present in the nose and the throat, or the test may be performed on the nose or throat alone.

Available test types

There is a “rapid” form of the PCR test that takes 15-30 min for results, and a less rapid form that can take anywhere from 1-7 days depending on where the test is run. The “rapid” PCR tests have been in short supply in the medical community and are often reserved for hospitals.

The antigen test is another rapid test that looks for pieces of protein that make up the SARS-CoV-2 virus in the nose or throat. One potential issue with this type of test is that there is a higher risk for a false negative antigen test if a patient doesn’t have a large amount of virus protein present. Antigen tests are also in short supply and are not currently available in most clinics.

Detecting current vs. prior infection

Both the PCR and antigen tests are used to detect acute (current) infection. The antibody or serology test is a blood test that looks for evidence of an immune response to the virus and is best for detecting prior infection. The ideal time to test for current infection is 2-3 days after the onset of symptoms.  For people who don’t have symptoms but have been exposed to COVID-19, the best time to test is 5-7 days after exposure.  The lack easily accessible, accurate, rapid testing has made our response to the virus very challenging!

At this time, the advice I offer to parents is this: Stay up to date on the most current guidelines, like those available from MDH and linked to above. If you are unsure about symptoms, consult your pediatrician and they will be able to guide you in the best course of action regarding testing.