Manila halts use of rapid antibody tests

MANILA has stopped the use of rapid antibody test kits to determine residents infected with the coronavirus disease 2019 (Covid-19) amid warnings of the inaccuracy of the results, the city government said.

Mayor Francisco “Isko Moreno” Domagoso said the local government would now use serologic tests, which the local chief executive hailed as the “nearest” to confirmatory reverse transcriptase polymerase chain reaction (RT-PCR) swab test in terms of accuracy.

“We used the rapid test kits because we got it for free. But nowadays, we don’t use it anymore,” said the mayor in a dzBB interview.

Manila employs the serologic tests, which use blood to detect the virus but which have a “sensitivity rate” of 99.6 percent.

Sensitivity rate is the capability of the test to identify  the antibodies to SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus which causes Covid-19.

Manila has conducted some 192,000 rapid antibody tests before switching to serology tests.

Heeding the national government’s guidelines, the local government still requires the confirmatory RT-PCR tests for those who test positive on serologic tests since they may not detect antibodies when the body’s immune response is still building up.

The Department of Health (DoH) has been consistent in warning the public about the accuracy of the antibody tests, citing high false positivity rates. But many local government units and private businesses used the test as a requirement for employees returning to work, which the DoH does not support.

Source: TheManila Times