Rapid antibody test shouldn't be used to rule out Covid-19: DOH

By Ma. Teresa Montemayor

August 5, 2020, 8:21 am

<p>Rapid antibody testing in Manila <em>(PNA file photo)</em></p>

Rapid antibody testing in Manila (PNA file photo)

MANILA – Rapid antibody testing should not be used as a stand-alone test to definitively diagnose or rule out coronavirus disease 2019 (Covid-19), the Department of Health (DOH) reiterated anew on Tuesday.

In a message to reporters, the DOH said this is stated in Department Memorandum 2020-0258 and that the reverse transcription-polymerase chain reaction (RT-PCR) testing remains to be "the primary basis and gold standard for diagnosing Covid-19."

In the early days of the pandemic when the country was placed under strict quarantine measures, the DOH cautioned that rapid antibody tests may not give accurate results and may show false-negative results.

The health department made the remark in response to issues raised by some medical organizations that rapid antibody testing does not accurately detect if a person is infected with Covid-19 and that it gives false security for those who have tested negative for the disease.

"The Health Technology Assessment Council has recently given their recommendations to the DOH with regard to rapid antibody tests (RATs). The HTAC does not recommend the use of RATs as a stand-alone test, irrespective of RT-PCR result and this is also the reason why, as stipulated in our guidelines, consultation with a doctor with regard to rapid antibody testing is necessary to ensure proper timing of testing and correct interpretation of results," the DOH said.

The department is in the process of developing omnibus guidelines on the use of the different types of test kits to "strictly specify the different types of tests and the conditions under which they may be used."

Rapid test kits can provide results within minutes after extracting a blood sample from a patient, which is faster than the 24- to 48-hour time frame needed to determine if a person is Covid-19 positive, based on swab samples from the throat and nose.

However, rapid test kits only detect the presence of antibodies or protein found in the blood that is produced in response to foreign substances.

Traditional kits are deemed more accurate as they are processed through the RT-PCR machine that can detect the presence of the actual coronavirus.

Health authorities said rapid tests complement the existing capacity of the country to conduct RT-PCR testing. (PNA)