RT-PCR test still effective in SARS-CoV-2 detection

MANILA –The reverse transcription-polymerase chain reaction (RT-PCR) test remains the most effective to detect SARS-CoV-2, the virus causing coronavirus disease 2019 (Covid-19), Health Undersecretary Maria Rosario Vergeire said Saturday.

The statement came in the wake of a report that a new variant that can evade some test has been detected in France last month.

“Ito pong article na lumabas na ito ay napakaliit noong population na nakitaan nila na hindi nadetect apparently sa RT-PCR pero ito naman po ay pinabulaanan din ng mga experts coming from Johns Hopkins, Stanford, at iba pang credible institutions (The concerned population whose infection was not detected through RT-PCR was small, but this was corrected by experts coming from Johns Hopkins, Stanford, and other credible institutions),” she said in a Laging Handa briefing.

“Ang sinasabi nila, RT-PCR not only uses the S gene, mayroong iba’t ibang genes na ginagamit for us to detect the virus so ‘yong nakita nila na nag-fail sa S gene o ano pang gene na ginamit, sa ibang gene hindi naman daw nakita ‘yong ganyang pagbabago so bottomline would be pag-a-aralan pa (They said that RT-PCR does not only use the S gene, it can also identify other genes to detect the virus. So what they failed to see was the S gene. In other genes, no change was observed so the bottom line here is that they’re still studying this),” she added.

Eight patients in the Côtes d’Armor in northwestern France reportedly showed typical symptoms observed in a Covid-19 case but their nasopharyngeal samples turned out negative in the RT-PCR test.

The French Ministry of Health said the diagnosis had to be made by serology or by performing RT-PCR on deep respiratory samples.

Vergeire, meanwhile, recognized the need to further develop existing tests to adapt to the emerging Covid-19 variants.

“Ang sinasabi ng mga eksperto all over the world because of these variants, ito po ay isang bagay na dapat pag-aralan ng lahat ng gumagawa ng diagnostic testing because baka in the future ito ay maka-apekto sa testing but for now ang sinasabi nila, itong RT-PCR testing is still very effective to detect the virus (Experts said there’s a need to further study how variants will affect diagnostic testing, but for now, they agree that RT-PCR testing is still very effective to detect the virus).”