Get to know PCR tests for diagnosing COVID-19

PCR or polymerase chain reaction is a laboratory examination to detect the presence of genetic material from cells, bacteria, or viruses. At present, PCR is also used to diagnose COVID-19, by detecting the genetic material of the Coronavirus.

Genetic material that is in each cell, including bacteria or viruses, can be DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). Both types of genetic material are distinguished from the number of chains in them.

DNA is a genetic material with a double chain, while RNA is a genetic material with a single chain. The DNA and RNA of every living species carry unique genetic information.

The existence of DNA and RNA will be detected by PCR through amplification or propagation techniques. Now, with the presence of PCR, the presence of genetic material from several types of diseases caused by bacterial or viral infections will be detected and ultimately can help diagnose the disease.

Some diseases that can be diagnosed through a PCR test are;

• Human immunodeficiency virus (HIV) infection
• Hepatitis C
• Cytomegalovirus infection
• Human papillomavirus (HPV) infection
• Gonorrhea
• Chlamydia
• Lyme disease
• Pertussis (whooping cough)

In addition to diagnosing a number of diseases above, a PCR test is also used to detect the Coronavirus that causes COVID-19. COVID-19 is an infectious disease caused by the SARS-CoV-2 virus which is more commonly called the Coronavirus. The Coronavirus that causes COVID-19 is a type of RNA virus.

PCR test for diagnosing COVID-19

The examination procedure begins with a sampling of sputum, phlegm, or fluid from the nasopharynx (the part between the nose and throat), oropharynx (the part between the mouth and throat), or the lungs of patients suspected of being infected with the Coronavirus.

Sputum sampling is done by the swab method, the procedure takes about 15 seconds and does not cause pain. Furthermore, sputum samples will be examined in the laboratory.

Well, because the Coronavirus that causes COVID-19 is an RNA virus, the detection of this virus by PCR testing will begin with the process of converting (changing) RNA found in the sample into DNA.

The process of converting viral RNA into DNA is carried out with the reverse-transcriptase enzyme, so the RNA virus inspection technique by converting it first to DNA and detecting it by PCR is called reverse-transcriptase polymerase chain reaction (RT-PCR).

After the RNA is converted into DNA, then the PCR tool will amplify or reproduce this genetic material so that it can be detected. If the PCR machine detects the Coronavirus RNA in the sputum or phlegm sample examined, then the result is said to be positive.

PCR Test to Ensure Rapid Test Results

In addition to the PCR test, you may have heard of the serological rapid test for COVID-19. Actually, a rapid test is not a test to diagnose COVID-19. A rapid test is simply a screening or screening test to detect the presence of IgM and IgG antibodies that the body produces when exposed to the Coronavirus.

Keep in mind, the formation of IgM and IgG antibodies requires a long time, which can be up to 2-4 weeks after the virus enters the body. Therefore, negative results on a rapid test cannot be used as a determinant for someone not infected with Coronavirus.

Positive results on rapid tests also can not be used as a determinant that someone is infected with the Coronavirus. This is because the antibodies detected can be IgM and IgG formed by the body due to other viral infections, including viruses from the coronavirus group other than SARS-CoV-2. Results like this are said to be false-positive results (false positive).

This is where the importance of doing a PCR test. The PCR test will confirm the results of the rapid test. To date, the PCR test is the most accurate diagnostic test to determine whether a person has COVID-19 or not.

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