The acronym PCR stands for a polymerase chain reaction. This test detects genetic material from a particular organism, such as a virus. If you own a virus at the time of the trial, the test will see its presence. The test could see viral bits even after the infection has resolved.
What is a PCR test for COVID-19?
The PCR test for COVID-19 is a molecular test that looks for genetic material (ribonucleic acid or RNA) of SARS-CoV-2, the virus that causes COVID-19, in upper respiratory samples. Using PCR, scientists amplify small amounts of RNA from specimens into deoxyribonucleic acid (DNA), duplicated until SARS-CoV-2 is detected. The PCR test has been the gold standard for COVID-19 diagnosis since its approval in February 2020. It is accurate and trustworthy.
Who should undergo COVID-19 testing?
If you exhibit any of the following symptoms, your healthcare professional may recommend a test for COVID-19:
- Fever or shivering.
- Breathlessness or trouble breathing.
- Body or muscle aches.
- New taste or smell loss.
- Painful throat.
- Congestion or nasal discharge.
- Sickness or vomiting.
Not all people infected with COVID-19 exhibit symptoms. And not all sick individuals exhibit all of the above symptoms. Even if you’ve been vaccinated, you should contact your healthcare practitioner if you feel ill during the COVID-19 pandemic.
COVID-19 diagnostic tests may be performed to determine if you are currently infected with the virus that causes coronavirus disease 2019 (COVID-19).
The U.S. Food and Drug Administration (FDA) has authorized the following COVID-19 diagnostic tests:
This COVID-19 test, also known as a molecular test, detects the virus’s genetic material using a laboratory technique known as reverse transcription polymerase chain reaction (RT-PCR). A fluid sample is obtained by inserting a long nasal swab (nasopharyngeal swab) into your nostril and removing fluid from the back of your nose. Using a shorter nasal swab (mid-turbinate swab) or a very short swab, a sample can be obtained (anterior nares swab). In certain instances, a medical expert will introduce a long swab into the back of your throat (oropharyngeal swab). Alternatively, you may spit into a tube to obtain a saliva sample.
If performed on-site, results may be available in minutes but may take between 1 and 3 days — or more in places with test processing delays — if transferred to an external lab. When conducted correctly by a medical practitioner, RT-PCR tests are highly accurate, although the quick test may miss some cases.
This COVID-19 test detects specific viral proteins. Certain antigen tests can yield results within minutes using a long nasal swab to collect a fluid sample. Others may be referred to a laboratory for examination.
When instructions are followed precisely, a positive antigen test result is deemed accurate. However, there is an increased likelihood of false-negative outcomes, suggesting that it is possible to be infected with the virus despite having a negative test result. The healthcare professional may propose an RT-PCR test to confirm a negative antigen result, depending on the circumstances.
The Flu SC2 Multiplex Assay is an RT-PCR assay that may simultaneously detect the COVID-19 virus, influenza A, and influenza B. (flu). A single sample is sufficient to see all three viruses. This may be useful throughout the influenza season. However, a negative result does not rule out any of these infections. Depending on symptoms, potential exposures, and your provider’s clinical assessment, the testing procedure may involve additional phases.
What occurs during an actual COVID-19 nasal swab test? How does COVID-19 testing work?
The examiner will place a long stick with a very soft brush on end — similar to a pipe cleaner — into your nose and rotate it for a few seconds. There, the soft bristles will gather an analysis-ready sample of secretions. The swab must reach quite far back because cells and fluids must be collected from the entire pathway connecting the base of the nose to the back of the throat to obtain a truly representative sample.
However, because the body is not accustomed to having an object in that location, it produces several highly strange sensations. Firstly, it activates the lachrymal reflex, which will cause tears to form in your eyes if performed correctly. I wouldn’t say it hurts, but it is certainly uncomfortable. Because the swab will also contact the back of the throat, it may also induce a gag reaction.
Are there further COVID-19 tests available?
Yes, different specimen forms that are less intrusive, such as a throat swab, can be used for testing. However, they lack the sensitivity of the COVID-19 nasal swab test. Saliva is another material being investigated, but the jury is still out on this one. The preliminary statistics are encouraging. However, more significant research are still required to corroborate these preliminary findings.
Antigen testing reveals the presence of viral proteins that stimulate the development of antibodies or the immune system’s reaction to invading organisms.
Antigen assays are considerably less sensitive than nucleic acid testing but being substantially faster. Consequently, a positive antigen test is instructive, whereas the more sensitive nucleic acid test must confirm a negative result.
Using nasal or oral samples, viral tests check for a current infection with SARS-CoV-2, the virus that causes COVID-19. Antigen testing and nucleic acid amplification tests (NAATs) are the two most used types of viral tests. In particular situations, one test type may be favored over another. All testing must be conducted following FDA regulations.
NAATs, including PCR-based tests, are typically conducted in a laboratory. They are often the most reliable tests for both symptomatic and symptom-free individuals. These tests detect viral genetic material, which may remain in the body for up to 90 days following a positive test result. Therefore, if you have tested positive within the last 90 days, you should not utilize a NAAT.
Rapid antigen tests yield results within 15 to 30 minutes. They are less reliable than NAATs, especially for symptomless individuals. A single negative antigen test result cannot exclude the possibility of infection. A negative antigen test should be repeated 48 hours apart for optimal infection detection (known as serial testing). Sometimes a follow-up NAAT is recommended to validate the results of an antigen test.
Self-tests, often known as at-home tests, are typically antigen tests that may be administered anywhere without the need to visit a specialized testing location. Follow the FDA and manufacturer’s recommendations, including the frequency of testing that may be required. Multiple negative test results increase the likelihood of not being infected with the COVID-19 virus.