There are a total of 43 laboratories in both public and private sectors currently involved in running COVID-19 tests, including universities labs such as Universiti Malaysia Sarawak (UNIMAS). We speak to Dr Tan Cheng Siang, Head of Centre for Tropical and Emerging Diseases, Faculty of Medicine and Health Sciences, UNIMAS to find out what goes on behind the labs.
What is the current capacity for testing in your lab? On average how many tests are being conducted in a day?
“Our current capacity for COVID-19 diagnosis is about 144 samples per day and currently testing about 60-80 samples daily. We can increase the capacity with the multiple of 48 which is the capacity of the equipment used.”
Guide us through, what is the process like of testing each sample?
“The ‘gold standard’ for SARS-CoV-2 detection is reverse transcription real-time polymerase chain reaction (RT-qPCR). This is the most sensitive method to pick-up the early stage of an infection. When the samples (throat swab) arrived at my lab, there will be a few steps involved. Validation of identity, Viral RNA extraction, RT-qPCR and reporting.
Viral RNA extraction is being done manually and it has 3 steps: Lysis (the use of chemicals to break open the viral envelope to expose its RNA genome). The RNA will then be adsorbed onto the surface of fine glass powder, Washing (the RNA bound to the glass will be washed with alcohol-based detergent to rid of contaminants) and finally elution (RNA will be solubilised in water and collected for the next step). The bottleneck is the viral RNA extraction steps as it is laborious and limited by the capacity of the equipment used.
The RT-qPCR step uses commercial RT-qPCR kit which has been standardised by the manufacturer but requires an expensive real-time thermal cycler to function.”
How long does it take to process each sample before getting the test results?
“We need at about 4-5 hours to obtain the results.”
What are the current challenges faced when testing for COVID-19?
“Supply chain disruption due to worldwide shortage of diagnostic equipment, personal protective equipment, RNA extraction kits and RT-qPCR reagents. Some laboratories lack expertise in RT-qPCR as it is considered a premium technology.”
Health DG revealed Malaysia had 8,000 pending test results. What would be a good strategy to address the backlog?
“Automation is probably the only way forward to clear the backlog of these tests. A complete automation is desired but partial automation on the viral RNA extraction would significantly reduce the backlog of these tests.”
Which country is leading in terms of testing and how can we emulate them?
“South Korea offers community-based screening and we might be able to emulate them. Nevertheless, South Korea manufactures the RNA extraction and RT-qPCR kits which may reduce their cost per test.”
Bio notes of expert
Dr Tan Cheng Siang is the Head of Centre for Tropical and Emerging Diseases, Faculty of Medicine and Health Sciences, University Malaysia Sarawak. A trained virologist, he has more than 20 years experience in handling infectious viruses, virus isolation and identification, phylogeny, molecular epidemiology, recombinant protein expression and diagnostic tool development. He is also a certified biosafety officer and holds four Certified Professional credentials from the International Federation of Biosafety Associations (IFBA).
**All previous posts about COVID-19 here: https://sciencemediacentremalaysia.com/tag/covid-19/