What are the different kinds of coronavirus tests?

Coronavirus testing
Photo via New York National Guard/Flickr (CC BY 2.0)

During the pandemic, one of the smartest things a person can do for their fellow humans is to get tested for coronavirus. According to the CDC’s newest guidelines, you should only get tested if you are experiencing actual symptoms of the disease. If you are spending quarantine time with a vulnerable individual or are concerned about the safety of your pod, however, there are three types of coronavirus tests you can consider. Two can tell you whether you’re currently infected, and another can detect if you’ve had the virus in the past.

Viral test

You can get a viral testalso known as a genetic test, molecular test, or PCR (polymerase chain reaction) test—if you want to find out if you are currently infected with COVID-19. If you’ve recently experienced symptoms of COVID-19 or if you have been in close proximity (within six feet for at least 15 minutes) of someone who is a confirmed coronavirus patient, this is the test to go for.

To administer the viral test, a healthcare provider will need a sample of saliva or mucus to determine if it contains bits of the virus’ genetic material. The most common way of taking the sample is by using a long nasal swab and sticking it into the nose to swipe different areas of the nasal cavity. A swab can also be used to take samples from the throat, the inner cheeks, or along the gums or tongue. PCR tests are reportedly very accurate when properly performed and when enough samples are taken. Unfortunately, rapid tests are known to miss some cases.

Another method of taking samples is giving a person a container to spit or cough into. Saliva-based tests are gaining popularity as an option because they are less uncomfortable and more kid-friendly.

After the samples are taken, they are either analyzed onsite or are sent to a lab for processing, which usually takes several hours. The time it takes to get your results back depends on the type of test and where the sample was sent for testing—it could take between 10 minutes and a few days, if the lab processing your samples has a backlog. 

Antigen test

A newer type of test that lets you know if you currently have COVID-19 is the antigen test, an option that detects certain proteins on the surface of the virus. Fluid samples for the antigen test are taken using the same nasal or throat swab method as the viral test. The only difference is the antigen test can produce results in a shorter time, these tests are generally more affordable, and they require less specialized lab equipment to analyze. This makes the antigen test a good option for groups of people. 

According to Mayo Clinic, a positive antigen test result is considered highly accurate, but chances for false-negative results are high. If the latter happens, doctors may recommend getting a viral test to confirm a negative antigen test result.

Antibody test

An antibody test can tell you if you were previously infected with the virus by checking your blood for antibodies. These are disease-specific proteins that fight off infections in the body. Also known as a serology test, this type of coronavirus testing is usually done after achieving full recovery from a confirmed positive COVID-19 diagnosis. Eligibility to get this test may vary depending on its availability in your location.

To get a sample for the antibody test, a healthcare professional will take a blood sample, either by pricking a person’s finger or drawing blood from a vein in the arm. The sample is then tested to see whether COVID-19-specific antibodies are present in your system.

If your results show you are positive for COVID-19 antibodies, it is highly likely that you have contracted the disease in the past and may have some immunity to it. There’s not a lot of data to date on whether antibodies can actually protect you from coronavirus reinfection, however.

This type of test will not be able to tell if a person is infected with coronavirus at the time the test is taken. Antibodies are created by the body anywhere between one to three weeks after infection. If you test too early, antibodies may not be detected at all. It is recommended to wait until at least two weeks after the first appearance of symptoms.

Antibody testing is useful for potentially treating COVID-19 in other patients. If your test reveals you have antibodies for the virus, you may be able to donate plasma, a part of the blood that, when injected into another patient who currently has COVID-19, may boost their ability to fight the virus.

President Donald Trump tested positive for COVID-19 on Oct. 1, but it’s unclear exactly which test he was given. “I’m not going to get into exactly what type of test,” Press Secretary Kayleigh McEnany told reporters the next day. In July, CNN reported that Trump was taking Abbott rapid tests. It’s also unclear how often Trump was tested before his positive diagnosis, and even after he recovered, Trump has refused to say whether he got tested the day of the first presidential debate.

Sources: AP News, CDC, Mayo Clinic, National Human Genome Research Institute, KidsHealth 

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