What Types of Tests Are Available for COVID-19?
Since the start of the COVID-19 pandemic, access to testing has been one of the biggest concerns among patients, healthcare professionals, and government officials. The United States has ramped up coronavirus testing over the last few months, helping to provide a more accurate picture of the true number of patients infected by the virus.
Now that COVID-19 testing has become more readily available, more patients who are experiencing symptoms are able to get a test. But with all the different types of coronavirus tests being discussed on the news and in the medical community, new questions have been posed: what are the different types of COVID-19 tests, which is the best test to get, and how long does it take to get COVID-19 test results back?
COVID-19 Diagnostic Testing
Diagnostic tests are used to identify active coronavirus infections. These tests are administered to patients who are currently experiencing COVID-19 symptoms, or who believe they have been recently exposed to COVID-19. When a patient receives a positive diagnostic result, it means they have an active infection and need to take steps to quarantine and isolate from others to keep from spreading the virus.
Currently, there are two main types of diagnostic tests being used for COVID-19:
COVID-19 PCR Testing
Polymerase chain reaction (PCR) tests make up the majority of tests used to diagnose patients with active COVID-19 infections. This type of test is also known as a viral test, molecular test, or nucleic acid amplification test (NAAT).
The COVID-19 PCR test works by detecting the genetic material of the virus in a fluid sample collected from the patient. A nasal or throat swab is the usual method of sample collection.
If the test is completed onsite, the results could be available to the patient in minutes. However, due to the volume of testing demand, most samples are sent to offsite labs. Results are usually available to the patient between one day and one week after testing.
The COVID-19 PCR test is considered to be highly accurate at diagnosing active infections and usually does not need to be repeated. Keep in mind that this test cannot tell whether or not a patient has been infected in the past, only whether they are currently infected.
COVID-19 Antigen Testing
Antigen testing is a more recently developed COVID-19 test that detects certain proteins on the surface of the virus. This type of test is also known as a rapid diagnostic test.
Much like the PCR test, the antigen test is performed by collecting a patient sample via nasal or throat swab. Antigen tests are faster and less expensive than PCR tests; there is no need to send the sample to an offsite lab, so the results are available within just a few minutes.
Compared to PCR tests, antigen testing is not quite as accurate. There is an increased risk of false negatives, meaning a negative COVID-19 antigen test not does definitively rule out the possibility of an active coronavirus infection.
If a patient is experiencing COVID-19 symptoms but receives a negative rapid test result, their physician may retest the patient using the PCR test to confirm or deny the original result.
COVID-19 Antibody Testing
Antibody tests are used to determine whether or not a healthy patient has been infected by COVID-19 in the past. This type of test is also known as a serology test or a serological test.
COVID-19 antibody tests are performed by collecting a blood sample from the patient (usually via finger prick, or sometimes by drawing blood from a vein in the arm), and testing that blood sample to detect the presence of certain antibodies developed after exposure to coronavirus.
Unlike the two diagnostic tests mentioned above, antibody tests cannot diagnose an active coronavirus infection at the time of the test, or be used as evidence that a patient does not currently have COVID-19. This is because antibodies take several days or weeks to develop after the infection.
Why is antibody testing important? Understanding the true number of patients who have been infected with COVID-19 is important for epidemiologists who are researching the spread and scale of the virus. This information will be essential in planning for future pandemics.
While it is possible that patients who have recovered from past COVID-19 infections may be immune from contracting the virus again, the World Health Organization cautions that there is no evidence to support this claim. Ongoing clinical studies will reveal more information about this in the future.
Another benefit of COVID-19 antibody testing is that people who have fully recovered from the virus may be eligible to donate plasma, which can be used to treat severely sick patients.
As the United States continues to navigate the COVID-19 crisis, all forms of coronavirus testing will play an important role in managing current outbreaks and preventing new ones.
If you are experiencing symptoms of COVID-19 testing, may have been exposed to the virus, or believe you have recovered from the virus, ask your healthcare provider about the best COVID-19 testing option for you.
Learn how My One Medical Source (MOMS) is working to meet the demand for COVID-19 testing at our MAPS locations.
Find our comprehensive list of COVID testing locations here.
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