KUALA LUMPUR – The RTK-Antigen (RTK-Ag) tests are typically able to detect the viral load after patients are infected between three and seven days, while the reverse transcription-polymerase chain reaction (RT-PCR) tests are good for infection day two to 14.
Health Director-General Tan Sri Dr Noor Hisham Abdullah said the accuracy of the two tests depends on the infection period when samples are taken.
This comes amid public complaints of differing test results obtained from the RTK-Ag and RT-PCR tests.
“After patients complete their quarantine, it is not necessary to repeat testing as sensitive tests such as the RT-PCR will still detect virus genetic material in the respiratory tract two to three months after. This is especially during the viral shedding period. However, the virus during this time will no longer be able to replicate or infect others.
“RTK-Ag tests are recommended for individuals who are symptomatic or are in a high-risk group if asymptomatic.
“Approved RTK-Ag test must have at least 95% sensitivity, leaving a 5% possibility of a false negative result. Other factors that may affect its results are contamination, cross-infection from other Covid-19 patients, wrong sampling technique and samples taken after the infection period.
He also shared a graph drawn from data by The Lancet medical journal.
“The Health Ministry approved the use of RTK-Ag as an alternative method of testing Covid-19 as it is simple, inexpensive, and can be performed in the field or point-of-care testing.
“The RTK-Ag testing process is fast and test results can be obtained within 20 to 30 minutes,” he said in a statement today.
“However, the RT-PCR tests remain the gold standard for Covid-19 infections as they detect specific virus genetic material, with a sensitivity up to 99.9%.
“This requires sophisticated lab equipment, higher costs, trained staffers and a longer waiting period of between six and 24 hours.”
He urged the public to report their results after the RTK-Ag self tests via MySejahtera and to update the status with the Home Assessment Tool as well as adhere to the latest quarantine standard operating procedures.
He said self-reporting will assist the ministry in getting a clearer picture of community infections.
As of February 18, there are 128 recommended self-test kits by the Malaysian Medical Device Authority. The public are able to cross-check their kits here. – The Vibes, March 6, 2022
