Ever since the FDA began granting more emergency use authorization (EUA) for COVID-19 testing, it has been more difficult to decide what type of test to get. In this blog, we will be discussing the types of testing, and the benefits/weaknesses of each.
COVID-19 is still new in the realm of viruses, and thus, information about tests is incomplete and ever-changing. With that being said, there are two types of COVID-19 tests, molecular and antigen tests.
The molecular test (also known as COVID-19 PCR test, viral RNA test, or nucleic acid test) can be administered a few different ways, primarily through tests of saliva or nasal/throat swabs. If you would like to get a molecular test, you can get it from a hospital, from inside your car at a healthcare facility, or at a medical office. Since December of 2020, the FDA has authorized LabCorp’s Pixel COVID-19 at-home test kit for use by anyone 18 years and older without a prescription. The molecular test aims to identify any genetic material of the SARS-CoV-19 virus in your system. The turnaround time for your results will depend on the speed of the lab they are sent to. Your results could be ready within a few hours, or they could be ready in a few days. At Biocollections, our current turnaround time for test results is 14 hours.
So how accurate are molecular tests? One great metric to measure the tests by is how often they produce a false-positive or false-negative result. Both of these results can have dangerous implications: if you receive a false-negative, you might be confident in going back out into the world and risk getting others sick. A false-positive result can force you to unnecessarily quarantine and complicate elements of your own life. The likelihood of receiving a false-negative test depends on how long the virus has been in your system. A study from the American College of Physicians found that the false-negative rate was around 20% when the test was performed within five days after symptoms first started to appear. Whereas the false-positive rate was much lower, and actually not due to complications of the test itself, but rather from contamination by the lab staff.
The antigen test (also known as the rapid test) is typically performed through a mouth or nose swab. Similar to the molecular test, you can get this done at a doctor’s office, hospital, or at home. As the name implies, the antigen test searches for antigens (a type of protein) that are attached to the virus. One of the largest benefits of taking this type of test is the rapid result you can get—results typically come within minutes of taking the test. The trade-off for getting such rapid results is that antigen tests tend to have more false-negative results than molecular tests. This has resulted in the FDA not recommending the antigen test to be the single test to identify active infection. Antigen tests are best used as screening tools for large populations, with PCR tests used as a backup to confirm results. Also similar to molecular tests, the chance you get a false-positive rapid covid test after a vaccine should be close to zero.
How Accurate are COVID19 Home Test Kits?
The convenience of being able to test for COVID-19 at home is great, especially for individuals where traveling outside the home can be a difficult task. There are benefits to utilizing a home test kit, but there are some weaknesses that we would like to inform you about as well. You can get both types of tests at home, and it will work relatively the same way as it would if you got it done at a doctor’s office for example.
Whether you choose to get a home test kit or not, the molecular test is still going to be more accurate. While the PCR test is the “gold standard” of testing, there are still certain cases when the antigen test would be preferential. Antigen tests work best early on in the course of an infection, so if you have recently been in contact with someone who has COVID-19, then taking an antigen test might be the right choice for you. As many of us are not medical professionals, there is always an element of human error that could come into play, with at-home testing. Make sure you read and follow the instructions very carefully if you choose to administer a home test.
Are Saliva Tests Just as Effective as Nasal Swabs to Diagnose COVID19?
Most samples of COVID-19 will be taken either from a nasal swab or a saliva test. In an analysis from JAMA Internal Medicine, they found that the nasal swab and saliva test came back with very similar results. The sensitivity of the saliva test was 83.2%, and the nasal swab test had a sensitivity of 84.8%. The biggest takeaway from this research is that either method is effective, but taking a PCR test will yield slightly more accurate results. If you have Covid-related symptoms, it is better to be on the safe side and assume you may be infected even in some minor capacity, and avoid giving it to others.
Our COVID-19 tests were among the first to receive emergency use approval in 2020. We are constantly working to provide the most accurate tests for our customers. We are able to deliver PCR test results to our customers within 12-24 hours. Contact BioCollections today to schedule a test at a lab near you.