8 November 2020 07:15 pm
The Rapid Antigen Detection Test (RADT) cannot be always used as a substitute for the PCR (Polymerase Chain Reaction) test for COVID-19 virus, Government Medical Officers’ Association (GMOA) Editor Dr. Haritha Aluthge said.
He said certain people seemed confused with the use of RADT and PCR tests.
"Both the tests detect the presence or absence of coronavirus antigen in the patient’s body, he said.
There are advantages and disadvantages when using the PCR and RADT, Dr. Aluthge said.
“PCR testing is costly (ranging from Rs.6,000 to Rs.8,000) and time-consuming, need human support and need more equipment when receiving reports. On-the-spot testing of samples cannot be done and samples need to be sent to separate test labs,” he said.
However, the RADT can give on-the-spot testing results in minimal steps than the PCR for a lower cost (at least Rs.1,000), he said.
“There should be a higher capacity of coronavirus antigen in a patient’s body to receive a tested positive result. Persons with a lower capacity of the virus will not get positive results from this method,” he said.
Based on the experiences of the professionals, the sensitivity of the RADT is lower than the PCR tests, he said.
However, a PCR testing should be done if the RADT tested negative and it is a must, he said.
“The RADT can be conducted as a point of care testing in high-risk areas only for screening purposes,” he said.
Therefore, Dr Aluthge said there is a place for the RADT but it cannot replace or be used as a substitute for the PCR. (Chaturanga Samarawickrama)