The latest Covid-19 update indicates a tremendous spike in infections, thanks to the Omicron variant. Safety protocols are back in full swing, as experts warn about adhering to wearing masks, sanitising hands, and maintaining social distancing.
However, it is also important to remember that prompt testing is also one of the effective ways to control the spread of the SARS-CoV-2 virus. Getting yourself tested at a reliable diagnostic centre is a must if you think you exhibit the symptoms of Covid-19 infection. Testing should also be done if you have been in close contact with anyone who has tested positive for the infection.
Covid-19 Testing: A Reliable Solution for Unpredictable Times
Thanks to the incredible advancement of medical sciences and technology, we now have hundreds of Covid-19 diagnostic tests at our disposal. Besides, the Food and Drug Administration has also granted Emergency Use Authorisation. This EUA allows makers to market tests even without FDA approval.
Our blog aims to shed light on some of the important Covid-19 testing options available today. These tests can diagnose current and past SARS-CoV-2 infections. In light of the ongoing public health crisis, awareness of these details is necessary to keep yourself safe.
Testing Options To Diagnose Current Infections
There are two types of tests to ascertain a current infection of the SARS-CoV-2 virus:
- Molecular tests
- Antigen tests
1. Molecular tests for Covid-19
The highly popular RT-PCR or Reverse Transcription Polymerase Chain Reaction test is the most commonly used molecular testing method to detect Covid-19. This testing method is considered the gold standard to test Covid-19 and has been used since the pandemic in 2020.
How an RT-PCR test works:
An RT-PCR test analyses a sample collected from the person and looks for the RNA of the SARS-CoV-2 virus. Phlebotomists use Reverse Transcriptase to convert small amounts of RNA into DNA. This method is replicated until the SARS-CoV-2 DNA is detected in the sample.
How is molecular testing done?
Swabs or long, soft sticks collect respiratory material from persons suspected of having Covid-19 infection. The collected swabs are sent to a laboratory where phlebotomists extract the genetic material from the sample. Using special chemicals, enzymes, and a thermal cycler, the genetic material is tested to detect the presence of the virus.
Turnaround time & Accuracy
Turnaround time for RT-PCR tests totally depends on the diagnostic lab's capacity. Some labs deliver the results within a couple of hours. While most labs take 24 hours to deliver the test results, much longer turnaround times are also possible.
As for the accuracy, RT-PCR tests are considered highly accurate and reliable. Experts say that nasal swab samples deliver accurate results than throat swab samples.
2. Antigen tests for Covid-19
Antigens are substances that trigger an immune response or trigger the generation of antibodies to protect the body. Antigen tests use lab-made antibodies to detect antigens from the SARS-Cov-2 virus.
An antigen test is also known as a rapid antigen test. The biggest advantage of antigen tests is that they can deliver faster results than molecular tests. However, the results may not be accurate because the antigen test has a higher probability of missing active infections.
Turnaround Time & Accuracy
Like a molecular test, an antigen test also needs swab collections from the nose or throat. Comparatively, the turnaround time is much lesser, and the results will be delivered within 15-30 minutes.
However, the FDA does not recommend the antigen test as a single reliable test for active infections. Most experts recommend repeating the test as a reasonable strategy to reconfirm the results. Additionally, similar to molecular tests, the false positive rate of antigen tests should be close to zero.
Covid-19 Tests Options To Detect Past Infections
The COVID-19 Antibody test, also known as a serology test, tests your blood for antibodies to COVID-19. The test determines if you were previously infected with the virus responsible for COVID-19. Antibody tests don't look for the infection itself but determine if your immune system has responded to it.
Antibody tests require only a blood sample, and you can expect the results within 1-3 days. However, some large diagnostic labs can deliver the results on the same day of sample collection.
Antibody Test Accuracy
The body takes at least two weeks to produce antibodies after a Covid-19 infection. Therefore an early antibody test may deliver inaccurate or "false negative" results. The reported rate of false negatives is 20%.
Other Tests Options To Diagnose Covid-19
Among the hundreds of Covid-19 testing options, we explore some of the popular methods experts rely on for diagnosing the infection.
Lateral Flow Test or LFT
Similar to PCR tests, LFTs detect active Covid-19 infection rather than antibodies. The testing method involves placing a nasopharyngeal sample on an absorbent pad. The pad is then drawn along a capillary line to a strip coated with antibodies that bind to SARS-Cov-2 proteins. If these proteins are present, they will appear on the test as coloured lines, indicating infection.
New Multiplex PCR test
The Multiplex Assay PCR test is a more robust, accurate, and efficient PCR test capable of detecting multiple viruses such as:
The Centre for Disease Control and Prevention (CDC) is expected to phase out the current RT-PCR tests favouring the Multiplex Assay PCR test in 2021-2022. This test will help determine what virus is causing the infection since the symptoms can be very similar.
There are two types of home testing options for Covid-19.
- A home collection where the samples are collected at home and sent to the diagnostic lab for further analysis.
- At-Home tests where you can collect the sample and use a testing kit to analyse the sample right at home.
You can get home tests with or without a doctor's prescription. However, you should clarify with your insurance provider whether your insurance coverage includes the cost of home tests.
ID NOW Covid test
ID NOW is a rapid molecular testing method that can deliver results in fifteen minutes. According to the CDC, tests like ID NOW have a moderate to high sensitivity. As far as ID NOW is concerned, it is more or less like an RT-PCR test and on the lower sensitivity end of the spectrum. Therefore, it is considered more accurate than an antigen test.
Will Covid-19 tests be able to identify the virus variant?
No, none of the Covid-19 tests will be able to identify which virus variant you have. To detect the variant, your sample must be analysed in a specialised genetic lab, where they are sequenced to identify the variants.
Moreover, not every positive specimen is tested; only sample amounts are taken. For example, if you hear that 75% of the cases in an area are a particular variant, that is an estimate based on the number of samples tested.
Stay Safe, Stay Guarded
How convenient would it be if we had an inexpensive option to test ourselves every time we returned home from work or school! With technology and science working together, such testing options may soon become available. However, we are fortunate to have so many testing options within such a short time frame. So, let's make the best use of them and bring the pandemic to an end.
Testing is a must to prevent the spread of the virus and to get timely treatment. Anderson Diagnostics & Labs, Chennai, is one of the leading centres that conduct the Covid Neutralising Test. Please contact our team to know more about this test.