MANILA – Polymerase chain reaction or PCR is the best test used for symptomatic patients of the coronavirus disease 2019 (Covid-19), a health official said Wednesday.

In a Covid-19 virtual presser Department of Health Undersecretary Maria Rosario Vergeire reiterated that "PCR (test) is very sensitive and can detect the virus or the virus genetic material or remnants".

Vergeire made the remark in response to Senate Majority Leader Juan Miguel Zubiri's question on the sensitivity of PCR test kits.

"Due to the test sensitivity, the PCR result of Senator Zubiri could be the remnant of the virus. It could also be false-positive result and/or cross-contamination," she said.

Vergeire added there were reports that patients can remain consistently PCR positive for many weeks or even test PCR positive after days or weeks of negative test.

"Recent available evidence suggests that eight days after the onset of the illness, viral culture had not been successful which correlates with the infectivity after the first week," she said.

On Monday, Zubiri said he skipped President Duterte’s State of the Nation Address after his reverse transcription-polymerase chain reaction (RT-PCR) test turned positive for Covid-19, contrary to the negative result of his rapid antibody test. (PNA