Learn the Different Types and Methods of Frequently Used COVID-19 Test

Answered by: Dr Sri Viknarajan
Updated on: May 6, 2020

Hi Doctor! I am Beverly, 23 years old. I am interested in knowing the methods used in detecting SARS-CoV-2. I have seen methods like taking nasal swabs on social media. However, I am curious if this is the only method to determine if one has this disease. What exactly is being done with the samples? I want to be well-informed so that I can spread my knowledge to my family members too. There are 2 cases in my neighbourhood. So, we want to be well prepared in case the health authorities decide to organise a mass contact tracing here. Thank you for your help, Doctor.
Hi Beverly! Thank you for your question. I am glad that you are a responsible citizen that wants to spread awareness regarding COVID-19. Samples can be taken from different parts of the respiratory system. Even blood samples can be utilised to investigate a patient for COVID-19. The methods used to identify the virus is the polymerase chain reaction. I will explain all of these in details in the following article on DoctorOnCall.

The recent influx of COVID-19 infections has left the frontliners be it scientists, pharmacists, doctors, and medical laboratory operators working hard to find a cure and the fastest way to detect the virus. The diagnosing test was enhanced to speed up the process of identifying infected patients while optimizing the treatment. Let see the different test that used to investigate this infection.

This method is already well known to the medical world and was first discovered and developed by a scientist named Kary Mullis since 1983. In addition to identifying viruses and bacteria, it has also been widely used in forensics. How does this test work? How can we identify someone was infected with COVID-19 using this technique?

Basically, this technique is capable of making millions of copies of Deoxyribonucleic Acid (DNA). DNA stores the genetic information of an organism including viruses, bacteria, and fungi. Through this process, the original copy of the DNA is multiplied and translated into comprehensible data. Information about the virus will be stored in and used to compare with the new genetic code of infection. This information simplifies and speeds up the process of identifying the types of pathogens that infect a person.

In the case of COVID-19 infection, the virus infects a person through the human respiratory tract and samples from this area. For instance:

  • Specimens from the upper respiratory tract: Samples were obtained from the nasal cavity or medically known as nasopharyngeal and oropharyngeal.
  • Specimens from the lower respiratory tract: The lower respiratory tract includes the lungs and bronchiole. Therefore the patient's sputum sample is used. Sometimes, lung tissue was extracted as the sample.

Once this sample is taken, it will be sent to the laboratory as soon as possible and stored at 4 degrees celsius. The sample will then be sent to the Institute for Medical Research or another specialized laboratory.

When a person is infected, the body reacts by producing antibodies to fight the virus. This antibody is specific to a virus. Therefore, the identification of specific antibodies in the blood can be used to identify the organism causing the infection and in this case COVID-19.

However, this method is only reliable after 7 or 14 days a person is infected with the virus. This is because antibodies only produced as early as 7 days after infection. This method is much faster compared to the PCR method and is also available in the form of rapid test kits. Usually, a small amount of blood will be taken for this test.

When this virus infected a person, it can cause inflammation of the respiratory tract, tonsils, throat and vital organs such as the lungs. This phenomenon alters the structure of the patient’s lungs and these changes can be seen on X-ray or CT scan of the chest.

During the early stage of this pandemic, doctors began to suspect the presence of this new virus due to abnormal changes in the X-ray image of a patient with shortness of breath. It is the earliest form of diagnosis of this infection and this method was widely used in China. Among the changes that can be detected in the lungs are signs of consolidation and hour-glass opacities.

In Malaysia, detection methods through the Reverse Transcriptase - Polymerase Chain Reaction (RT-PCR) and antibody identification by blood sample are the standard techniques used in every hospital that is managing COVID-19 infection. As research for a more rapid and precise test are still ongoing, the diagnostic test for this infection may be changing. Let’s pray for that as well as the cure.

Need Medication Advice?
Consult a doctor today. Ask Doctor for FREE

Online Pharmacy
Get your medicine delivered through DoctorOnCall Same day Medicine Delivery

About DoctorOnCall

This article is updated and maintained by DoctorOnCall. If you have any suggestions about the answer, please email us at contact@DoctorOnCall.com.my

Ask Doctor for FREE
RM30 ePharmacy Cash Rewards
Claim RM300 for COVID-19 Test >