Covid-19
The Coronavirus disease scared the world in January 2020. The infectious disease soon spread globally turning into a pandemic, restricting normal life and workflow and causing millions of deaths. Here is everything you need to know about this disease and the various tests available to detect it.
COVID-19 is a contagious disease caused by the SARS – CoV-2 virus. Most people infected with this disease will experience mild to moderate respiratory illness and may recover without needing any special treatments. However, some people with underlying medical conditions like cardiovascular disease, diabetes, cancer or chronic respiratory disease may develop serious illness after being affected by COVID-19. Anyone with this disease can get very sick at any age and die.
The virus can spread from an infected person’s mouth or nose in small liquid particles when they sneeze, cough, sing, breath, or speak. These particles can be large respiratory droplets to smaller particles. Practicing respiratory etiquette by placing a mask over their nose and mouth can prevent the spread of this disease. Infected people should self-isolate until they recover to avoid spreading this disease.
COVID-19 tests can detect either SARS-CoV-2 or biomarkers of SARS-CoV-2, the viruses that cause this disease, or antibodies that the body makes to fight these diseases. There are three main types of COVID-19 tests:
PCR Tests - Polymerase chain reaction (PCR) tests
A PCR test or a polymerase chain reaction is a test done to detect genetic material of the virus infecting the body. These tests detect the presence of virus in the body. It can also detect fragments of the virus inside the body even when the person is no longer infected.
The PCR test for COVID-19 is a molecular test to detect any traces of the virus in the upper respiratory specimen. It looks for genetic material such as ribonucleic acid or RNA of the SARS-CoV-2 in the specimen. A PCR technology is used to amply the specimens and to test whether the RNA is converted into deoxyribonucleic acid (DNA), which is replicated until the virus is present.
The PCR test is the standard test for diagnosing COVID-19. It is the most accurate and reliable test.
Lateral flow tests (LFTs)
A lateral flow test is done using a lateral flow device or Assay, to detect the presence of a target substance in a liquid sample without the need of any costly or specialized equipment.
It is a diagnostic device used to confirm the presence or absence of the virus in the upper respiratory sample taken. The nasopharyngeal sample is placed on the small absorbent pad, which is then drawn along the pad through a capillary line to a strip coated in antibodies, which bind to the SARS-CoV-2 proteins. If the sample has the proteins, a colored line will appear on the test, indicating a positive infection.
This is a very rapid and quick test with results coming out in 15 to 30 minutes. However, these tests are not quite accurate as the PCR tests.
Antibody (or serology) tests
A positive antibody test result indicates that the person has antibodies for COVID-19 owing to a past infection with this disease or vaccination against the disease.
While PCR tests use swabs to detect COVID-19, antibody tests use blood samples. The antibodies circulating in the blood are quite high following an infection or a vaccination.
Antibody tests are used to evaluate the immune responses in people who are vaccinated against the disease.