The Covid-19 crisis has made this clear that for the prevention and control of this deadly virus – SARS-CoV-2, their source needs to be identified. And to identify the source, i.e., the infected person, who can be symptomatic or asymptomatic, Covid-19 diagnostic tests are performed. Popularly, there are two types of tests that are widely used to diagnose the infection. These two tests are diagnostic tests and antibody tests. The molecular diagnostic test is known as the PCR test and the other one is the Antigen Diagnostic Test.
Testing is considered very important to stop the spread of the SARS-CoV-2 virus. What is the difference between PCR and Antigen tests? Which test is more accurate in detecting the virus or how much time is required to get the results? These are some of the popular queries on the web these days. Let’s find out the differences between an Antigen Test and a PCR test. In the coming sections, you can read about these two popular testing technique, their functionality, accuracy, and more.
What is the difference between PCR and Antigen tests?
Let’s quickly understand a few of the main differences between a PCR Test and an Antigen test. Here is a simple table of comparison for your easy understanding:
| Parameters | Antigen Test | PCR Test |
| Detects | Protein Fragments which are particulars of Coronavirus | Genetic substance, i.e. RNA |
| Time | Results in 15 minutes | Minimum 24 hours and may take 2-3 days as well. |
| Accuracy | More accurate with a person having clear symptoms | Can detect infection even if there are no symptoms |
| Requirements | A proper Testing Facility or lab is required to detect the result | Results are easily detected |
| Cost | Comparatively Cheap, costs around $10-$15 | Expensive, costs approx. $100 |
Though the purpose is the same each of these tests works on different functionality. Let’s read more in detail about Antigen Test and PCR test to understand the difference!
What is Antigen Test or Rapid Test and How it Works
Antigen tests work on highly symptomatic persons. A person with no symptoms which is possible in the case of Coronavirus may get a clean chit with an Antigen test. Who can have Antigen Test? A person who is infected with this highly transmissible SARS-CoV-2 virus and has clear symptoms of it might get true results with an Antigen test. If the person is at an early stage, detection of virus by Antigen test may not produce an accurate result. How does Antigen Test work? Antigen test works by activating the generation of antibodies in the patient.
The positives of the Antigen test are they are easy to conduct, doesn’t require many skills and specialization, and can be done even at home. The cost part is also comparatively low but, on the accuracy, you can’t blindly trust this test as you need to have enough amount of antibodies or the virus in your body to trust the accuracy of this test. Another plus of the Antigen test is the results are quick.
What is PCR Test and How it Works
PCR Test or as the full name suggests Polymerase Chain Reaction Test works on the technique of polymerase chain reaction to detect the coronavirus in the body. The PCR test works on genetic samples, by treating the sample with an enzyme that transforms RNA which is a molecule like DNA into two-stranded copies of DNA. Ribonucleic acid (RNA) is used to create double copies of the Coronavirus genes.
Well, that may be too technical, but talking about the positives of the PCR test, a PCR test can successfully detect even a small amount of coronavirus genes present in the body. So results are more trustworthy. The PCR test does have some shortcomings you may get a test done at a hospital or a clinic by a technician but the sample requires special equipment, a lab, and a skilled technician.
The results are not quick as in the case of a Rapid test or Antigen test as the process includes, the collection of samples, then transportation to the facility, processing the amplification process, its diagnose and then the final report. About the costing part, PCR tests are comparatively costly. Approximately a PCR test can cost you around $100, unlike the Antigen test cost which is done in the approximate range of$10- $15.