Self-test kits for frequent testing, not for Covid-19 diagnosis

The gold standard to confirm Covid-19 is still the RT-PCR test


COVID-19 self-test kits are only meant for frequent screening and should not be used as a replacement for an actual Covid-19 diagnosis.

Universiti Malaya Public Health Medicine specialist, Department of Social and Preventive Medicine, Prof Dr Victor Hoe Chee Wai Abdullah said those who receive positive results on their self-test Antigen Rapid Test Kits (RTK-AG) will need to undergo a reverse transcription polymerase chain reaction (RT-PCR) testing from the clinics.

The self-test kits are meant to conduct regular and frequent tests among high-risk people, such as those with comorbidities staying at home or workers with frequent exposure to the public. These types of tests would be able to have a higher probability of identifying Covid-19 positive cases.

“However, the use of the regular RTK-AG self-test kits should not replace the current standard operating procedures (SOPs).

“Prevention of Covid-19 needs a multi-layer approach such as the Swiss cheese approach,” he spoke to The Malaysian Reserve (TMR) via email recently.

SOPs such as wearing face masks, physical distancing, observing hand hygiene, and avoiding crowds, confined spaces and close conversation should continue, especially when in the workplace or in public areas.

The reliability of these test-kits also depends on the time of the testing. It is more likely to be accurate when the test is conducted on the highest virus load.

“The ability of the test to pick up people with Covid-19 depends on the viral load, antigen tests perform best in symptomatic people and within a certain number of days since symptom onset,” Hoe added.

Since it is also important to follow the instructions on the kit, the accuracy also depends on how the saliva or oral fluid has been collected.

“In a patient with symptoms suspected of Covid-19, when the first self-test kit results are negative, it should be repeated with another self-test kit or RT-PCR test at the clinic,” he explained.

Currently, there are a total of 64 Covid-19 RTK-AG self-test kits which have received conditional approval in the Medical Device Authority’s (MDA) website.

Some of these tests require saliva or nasal swab samples and Hoe believes that it is confusing for people to decide which test kit is suitable since there are so many choices available.

“However, the public must take comfort that all the kits that have been approved by the MDA would have met the minimal criteria set by the MDA.”

Hoe also mentioned that the self-test kits are based on the antigen produced by the body, unlike the RT-PCR which tests the Covid-19 presence in the body.

“The importance of updating the information is to ensure that their close contacts will be able to monitor themselves and self-quarantine at home if necessary.

“This will reduce the transmission of the virus,” Hoe said.

Meanwhile, the Malaysian Medical Association president Dr Koh Kar Chai said self-test kits are convenient and can be used anywhere and at any time.

It can also detect Covid-19 infections in a short period of time.

“However, the self-test kits do have their limitations and if a person tests negative using a self-test kit and still has symptoms, it is advisable to get to a doctor for a swab test to rule out Covid-19.

“The gold standard to confirm Covid-19 is still the RT-PCR test,” he told the TMR.

Another issue with the self-test kits is that there is a possibility that people will not update the health authorities when they test positive.

“This is unwise as a proper assessment of their condition and monitoring of their health needs to be done by healthcare professionals who are trained in the management of Covid-19,” said Koh.

“This will not be easy. However, a post-market surveillance needs to be done for us to understand the outcome of self-testing methods,” he explained.

Koh also advises that those who wish to purchase any self-test kits should make sure they have been registered with the MDA.

“All legitimately sold self-test kits have been approved by the MDA after being carefully checked and evaluated for safety and reliability.”