How are onsite swab tests conducted?

During disease outbreaks, a rush of patients seeking medical attention can overload healthcare facilities, necessitating a similar reaction from healthcare providers. 

COVID-19 may be tested using two methods: 

  • Diagnostic test 
  • Antibody test. 

Diagnostic tests

Antigen Rapid Test (ART) and Polymerase Chain Reaction (PCR) tests to search for active coronavirus infection in mucus or saliva, respectively. ART tests seek for the virus’s coating or proteins, whereas PCR testing looks for the virus’s genetic material, nucleic acid (RNA). 

Antibody tests

Antibody testing seeks antibodies to the coronavirus in persons who have been infected with it. Antibodies are proteins produced by the immune system in order to combat infection. Because it might take 1–3 weeks for your body to generate enough antibodies to be identified in a test, the timing and kind of antibody test have an impact on accuracy. 

Antibody tests are an excellent method to see whether you have had a lot of exposure to the virus in the past, but they should not be used to identify someone who has an ongoing infection since antibodies take a long time to produce after exposure.

A nasal swab is commonly used to collect samples of cells and fluids from the nose or throat, which are then analyzed by a machine that identifies the virus’s genetic information. A blood sample is used in an antibody test, also known as a serology test, to identify signs of the body’s immunological response to the virus following an infection.

Before having the self-testing swab kits, how did Singapore manage onsite swab tests?

Onsite swab tests were conducted a year ago and every day, there were hundreds of samples going in and out of the lab from suspected COVID-19 cases. 

They were personally carried by hand by representatives from NCID to be brought to the labs at Tan Tock Seng Hospital (TTSH). These representatives or “porters” transports the swab tests back and forth and there will be 13 to 15 of them on one shift. 

The samples being collected and checked were most likely high-risk suspects. The ministry of manpower has activated a Swab Registration System where potentially infected attendees can book their onsite swab test slots online.

So, how exactly are onsite swab tests conducted?

Below is a brief explanation of how swab tests are done and what you can take note of during and before the process. There are two ways of testing which include either through your

  • Nose
  • Oral 

If you are doing a nose swab test:

The nurse first ensures that the universal transport medium is in excellent working order and that it has not expired. The sample is preserved and kept in its original state using the transport medium. Transport medium is known to collect, transport, and preserve the specimens containing viruses.

After that, you will then be told to blow your nose. The nurse next tilts your head upwards to acquire a sample by inserting the swab stick into your nose. Remove the swab stick and deposit it in the universal transport medium.

This is then placed into a biohazard bag and disinfected (MICRO-CHEM PLUS detergent disinfectant cleanser, or ethanol) before being wrapped up for safety. The sample is double-bagged and cleaned once more before being sealed with a sticker as an extra precaution.

The biohazard bag is then sealed and placed upright in a canister. Before being transported to the laboratory for testing, the canister is put inside a biohazard box and cleaned off with a disinfectant.

  1. There will be tissues available. Blow your nose to get rid of all the mucus. When you have finished, toss the tissue paper into the biohazard waste container.
  1. Lift your chin and lean your head backward. For two to three seconds, a cotton swab will be inserted in each nostril, all the way to the back of the nose. 
  1. Keep in mind to remain still. Once the swab is complete, place the sample in a biohazard bag labeled with your name.

If you are doing an oral swab test:

  1. For around 2-3 seconds, a cotton swab will be inserted down your throat. Keep in mind to remain still. It can feel a little ticklish or uncomfortable.
  1. If you are in any pain or suffering, raise your hand. After the swab is completed, the sample is placed in a biohazard bag with your name written on it.

What happens afterward?

The specialist will mark each sample with a laboratory-generated accession number, which is a unique identifying number after the samples arrive at the lab. The sample transfer is done with care and attention to avoid cross-contamination. 

These samples will be sent to the testing equipment in a sealed container. The test may collect up to 94 samples in a single batch, which takes around 3.5 hours to process which can be very time-consuming.

Major clusters in Singapore and how were they managed?

Many clusters occurred this year and can be as major as the bus interchange which affected as many as 8 bus interchanges.

One of the major onsite tests was in Seng Kang and Jurong this year. Sengkang swab tests were made mandatory for residents of a flat in Sengkang West as some were tested positive for COVID-19. Thus, the entire block was called down for major onsite tests. They were urged to go to clinics to check. 

Jurong was also highly infected, especially at the Jurong Fishery Port and JEM shopping mall where there was a cluster. The government has designated facilities throughout Singapore and has urged those who visited the mall and the port to take free swab tests and were quarantined. The Jurong swab test was done in these facilities. That includes other clusters as well to do the same procedure.

Onsite swab test is done in the booth that is blue in color. The clinic will first ask you to fill in a form with details of your visit to the malls or anywhere infectious that has clusters happening. It is best if you are able to provide the time you visited the place.

If you are wondering about those who want to get tested right away, walk-in swab testing is now available to anyone who is not part of any clusters or has close contacts. These services are available at a number of clinics, but you will have to pay a fee. Raffles Place swab tests are common since the area is centrally located in Singapore and includes a variety of well-known clinics, such as Rafflesmedical and AcuMed Medical. Since the government approved their COVID-19 PCR and ART testing, a large number of people have visited these clinics. This also applies to other PHMCA-licensed clinics and hospitals that have been approved.

There are many methods of testing for COVID-19 which are made available now. It includes test kits and here is a table on how effective each method of testing for COVID-19  is.

Types of testsAdvantagesDisadvantages
Antibody TestAbility to show proof of the previous infectionNot suitable to identify active infections
Breathalyzer TestFast results Available only at traveling gates.
ART TestQuick and easy to doRelatively inexpensive May not be able to detect early stages of infection
PCR TestAccurate results Antigens are detected even before symptoms occurTime and labor-consuming

The manner the onsite swab tests are done to collect the test sample has a big impact on the accuracy of the swab findings. Because the sample may deteriorate over time, especially in hot conditions, the time it takes for the swab to reach the lab is also significant. The accuracy of the swab results is also affected by the time of infection. If the sample is obtained too early or too late, the test may produce a false-negative result.