COVID-19 testing basics

We’ve heard a lot about coronavirus testing recently. Let’s explore the different types of tests and what the steps are in the testing process.

NOTE: If you think you have coronavirus disease 2019 (COVID-19) and need a test, contact your health care provider immediately. 

Types of Tests

Many people don’t know that there are two different types of tests – viral (or "diagnostic") tests and antibody tests.

1. A viral test , also called a diagnostic test, can show if you have an active coronavirus infection and should take steps to quarantine or isolate yourself from others.
2.  An antibody test looks for antibodies that are made by the immune system in response to a threat, such as a specific virus. Antibodies can help fight infections. Antibodies can take several days or weeks to develop after you have an infection. Because of this, antibody tests should not be used to diagnose an active coronavirus infection.

Having antibodies to the virus that causes COVID-19 might provide protection from getting infected with the virus again. If it does, at the time of this writing we do not know how much protection the antibodies might provide or how long this protection might last.

Testing Process

Many companies and labs have developed tests to diagnose COVID-19 based on detection of the virus’s genetic material in a sample from the patient’s nose or throat. The typical steps in this type of  testing for the coronavirus are:

1. A health care professional orders a COVID-19 test. All COVID-19 tests, including those used with a home collection kit, require a prescription.
2. You or a health care professional use a specialized, sterile swab to collect mucus from your nose or throat.
3. You or a health care professional put the swab in a sterile container and seal it for transport to a lab.
4. During the shipping process, the swab must be kept within a certain temperature range to keep the virus alive so that the test will be accurate. The sample must arrive at the lab within 72 hours.
5. A lab technician mixes chemicals with the swab to extract the genetic material of any virus that may be on the swab.
6. The lab technician uses special chemicals, called primers and probes, and a high-tech machine to conduct several controlled heating and cooling cycles to convert the virus's RNA into DNA, and then make millions of copies of the DNA.
7. When DNA binds to specific probes, a special type of light is produced that can be seen by the machine and the test shows a "positive" result for infection with SARS-CoV-2, the virus that causes COVID-19.

More information about COVID-19 testing can be found on the FDA website.