RT-PCR vs. Rapid Antigen: The Two Critical Covid-19 Diagnostic Testing Methods

The most discussed, talked, researched, and brainstormed topic for the past two years has been the Covid-19 pandemic. The pandemic has been a disaster to say the least. More than 6 million people have lost their lives to the virus and millions more have been affected directly or indirectly. The Covid-19 pandemic has, along with the common populace, also troubled the scientific world a lot. The nature and the mutations of the SARS-CoV-2 virus has puzzled almost all medical experts across the globe. Since March 2020, when the World Health Organization declared Covid-19 outbreak as a pandemic, the scientific world focused their energies on three things:

• Developing a diagnostic test which will help in finding out if a patient is infected with the SARS-CoV-2 virus,
• Developing a vaccine to prevent the spread of the virus, and
• Developing a medical drug that would neutralize and treat the Covid infection.

As of today, the first two have been successfully developed, and even though the third one isn’t completely developed, various treatments have been devised which treat Covid successfully.

What are the Two Types of Covid-19 Diagnostic Testing Available?

Developing a full-proof Covid -19 diagnostic testing method was extremely crucial in order to identify whether a person is infected with Covid or not. Correct identification would, in turn, help in developing strategies to curb the spread of the virus and also address the panic and hysteria that was associated with Covid. With arduous research, the scientific community came up with two Covid-19 diagnostic testing methods:

1. RT-PCR Test

RT-PCR, short for Reverse Transcription-Polymerase Chain Reaction, was one of the first Covid-19 diagnostic testing methodologies devised across the globe. In this diagnostic testing method, a sample is collected from the person’s nose or throat with the help of a swab. The sample can be anything including blood, saliva, mucus, etc. The sample, thus collected, is then treated using various solutions and chemicals so as to extract the RNA out of it. The RNA, using reverse transcription method, is turned into DNA with the help of enzymes and if, in case, some fragments of the DNA are missing, then the complementary genetic fragments are added to it. If the virus is indeed present, these genetic fragments get latched on to the sample. The sample is then run through the RT-PCR machine which takes out identical copies of the DNA and this process is continued until around 30 billion copies of the DNA are made. The results are represented on the paper using a fluorescent dye; if the fluorescent color passes a specific threshold, it denotes the presence of the virus. RT-PCR is, thus, a reliable Covid-19 diagnostic testing method to find out whether the person is infected with the SARS-CoV-2 virus or not.

2. Rapid Antigen Test

Currently, RT-PCR test is the most opted Covid-19 diagnostic method available in the Covid-19 diagnostics market. However, RT-PCR is very time consuming due to which the test results take time. Hence, a new test known as rapid antigen test was devised which gives out test results within hours. This Covid-19 diagnostic testing method, instead of looking for the DNA in the virus, looks for the proteins that are present on the surface of the virus. A rapid antigen test kit is used in which the swab containing the sample is inserted so as to produce results. The control and test lines of the kit denote whether the sample contains the virus or not. One major advantage of rapid antigen test is the speed and convenience involved in testing. However, there is a trade-off; rapid antigen tests have tendency to produce false-negative results, meaning a person can be tested negative even if he/she has the virus. Hence, WHO has recommended using rapid antigen test only if RT-PCR isn’t available.

The Bottom Line

The importance of the aforementioned Covid-19 diagnostic testing methods can never be overstated. These two tests have helped at both the levels- at the individual level, it has helped in confirming whether or not a concerned person is infected with the SARS-CoV-2 virus; at the societal level, it has helped in gauging the extent of the spread of the virus which has further helped in chalking out administrative strategies to contain the spread of the virus.

About the Author(s)

Princy A. J

Princy holds a bachelor’s degree in Civil Engineering from the prestigious Tamil Nadu Dr. M.G.R. University at Chennai, India. After a successful academic record, she pursued her passion for writing. A thorough professional and enthusiastic writer, she enjoys writing on various categories and advancements in the global industries. She plays an instrumental role in writing about current updates, news, blogs, and trends.