Most people have had at least one COVID-19 test while the epidemic is still in its early stages. However, are you aware of the numerous types of tests you were given and the benefits and drawbacks of each?
For the diagnosis of SARS-CoV-2 infection, there are two main types of diagnostics: PCR and antigen assays. Tests can vary in speed and accuracy depending on the type of virus they are looking for. Do these tests differ in any significant way?
Forensic Testing Based on DNA Analysis
First, the patient must provide a specimen for testing. In this case, it could be a nose or saliva sample that needs to be examined.
To detect even a trace amount of coronavirus genes in patient samples, the next stage in PCR tests is to amplify genetic material such that even a trace amount can be discovered. Using a process known as a polymerase chain reaction, this is accomplished. After the sample is collected, a medical professional will use an enzyme to turn the RNA into double-stranded DNA. The polymerase is then heated to the DNA, resulting in the DNA splitting into two single-stranded fragments. A primer, which is a short bit of guide DNA, helps polymerase attach to the single-stranded DNA and copy it. Coronavirus DNA is amplified using primers that solely target the virus. Two copies of the coronavirus DNA have now been made using only one piece of RNA from which to start.
The DNA is duplicated a billion times in the laboratory using machines that go through this heating and cooling cycle 30 to 40 times. A machine can read the fluorescent dye in the amplified sequence.
Even the smallest quantity of coronavirus DNA can be detected because of PCR’s ability to amplify genetic material. Consequently, it’s a susceptible and precise test. The gold standard for diagnosing SARS–CoV–2 is this test, which has an accuracy rate close to 100 per cent.
PCR testing has drawbacks. The amplification procedure can take an hour or more to complete and requires specialised equipment and a trained laboratory operator. Many PCR tests can be performed simultaneously in extensive, centralised testing facilities. A person must complete several steps before receiving test results, ranging from 12 hours to 5 days.
Tests For Antibodies
Quick and reliable testing is required to contain a highly contagious virus such as SARS-CoV-2. PCR tests are highly accurate, but they can take a long time to generate a positive test result. Antigen tests, the other significant coronavirus test type, are faster but less reliable.
Antigens are chemicals that elicit an immunological response in the body, producing antibodies. These techniques use antibodies generated in the lab to look for antigens from the SARS-CoV-2 virus.
Antigen testing is done by first soaking a sample in an antiseptic solution that dissolves cells and any other particles that may be present. After that, a thin line of anti-SARS-CoV-2 antibody is painted on a test strip with this liquid.
Antibodies on the test strip will bind to any antigen in the sample, just like the antibodies in your body are designed to do. Antibodies that bind to coronavirus antigens produce a coloured line that indicates the presence of SARS-CoV-2 on the test strip.
The advantages of antigen tests are so simple to use and understand results without special training. They also deliver benefits immediately, on average, within 15 minutes of starting. Another advantage is that they might cost less than 10 to 15 per test.
A few limitations do exist with antigen tests. They may be less accurate than PCR testing in some circumstances. Antigen testing is proper in cases where a person shows signs of illness. Antigen tests, in contrast to molecular PCR testing, do not amplify the thing they are searching for. The antibodies on the test strip need to detect enough viral antigen to detect a signal. Taking samples from the nose and throat in the early stages of infection is difficult because there isn’t much virus present. Antigen tests in the early stages can miss COVID-19. During this stage, a person is more likely to go unnoticed because they don’t have any symptoms.
More Tests Mean Better Preparation.
The FDA has granted only a handful of at-home antigen tests emergency use authorisation, but others are already available over the counter. Furthermore, the British government is pressing for greater public access to these examinations.
The covid-19 pandemic can be brought under control with PCR and antigen tests used in conjunction with each other. When you retake the COVID-19, be sure to select the option that is most appropriate for you.
