Covid-19 saliva test eyed to expand testing capacity

MANILA – The saliva-based Reverse Transcription Polymerase Chain Reaction (RT-PCR) test for Covid-19 is seen to expand the country’s testing capacity, a health official said Wednesday.

In an online media forum, Department of Health (DOH) Undersecretary Maria Rosario Vergeire said the test that detects the virus in saliva could make coronavirus testing easier and cheaper.

“Mas mura siya by as much as half kaya ang gobyerno talaga, tinitignan natin ang possibility kung paano natin pwede ipasok sa program natin ‘yan para mas mabilis ang resulta, kasi mabilis na siya. Mas mura siya so therefore mas magiging efficient ang ating gobyerno kapag ginamit natin ‘yan (It is cheaper by as much as half so the government is looking into the possibility of including it in our program. Results come out faster. It is cheap, therefore we become more efficient when we use such testing),” Vergeire said.

The test allows saliva samples to be collected in a sterile container and employs a much less invasive process than nasal swabs.

“Mas madali siya gawin. Pangalawa, mas tipid siya kasi hindi na gagamit ng mga swabs and re-agents para maayos mo ‘yung saliva para ma-proseso mo (It’s easier to do. It is cost economical because you don’t have to use swab and re-agents to process the [specimen]),” Vergeire said.

“Mas konting PPE [personal protective equipment] ang ginagamit ng healthcare workers and lesser chances of them being exposed kasi ‘yung tao na po ang dudura doon sa mismong paglalagyan ng saliva. And mas mura siya (fewer PPE to be used by the healthcare worker and lesser chances of them being exposed because the person simply has to spit onto the container. And it is cheaper) by as much as half),” she added.

In the country, the Philippine Red Cross launched the saliva-based testing last January 25.

The PRC still remains to be the only one conducting such tests but Vergeire said some laboratories are undergoing validation to do the same.

The saliva-based test goes through the same RT-PCR method to produce results. It differs from the nasopharyngeal and oropharyngeal swab tests only with the specimen it uses – saliva.

“Nakita naman natin na (We saw that [the saliva-based test] has acceptable accuracy and concordance with the nasopharyngeal and oropharyngeal swab, but we continue to monitor not only at the PRC, the RITM (Research Institute for Tropical Medicine) has a mandate as the national reference laboratory to do the monitoring and quality assurance of all the laboratories,” Vergeire said.

A person may choose which among the tests he prefers, whether saliva-based, nasopharyngeal or oropharyngeal, she said.

“If you go to a laboratory offering already both of these, it’s your choice, you’re [the one] going to pay, but at the moment, other laboratories are still working to set up their own have saliva as specimen implemented also in their laboratories,” she added.

Under Department Memorandum No. 2021-0161, the DOH said licensed coronavirus disease 2019 (Covid-19) laboratories certified by the RITM are allowed to perform the test since they use kits validated by and registered to the RITM and the Food and Drug Administration.

Only trained saliva specimen collectors should administer the test and only medical doctors should interpret the results of these tests.

Morning saliva is preferred as a specimen due to higher viral load but this should not prevent specimen collection at any other time.

Patients should not eat, drink, brush their teeth, use mouthwash or smoke for at least 30 minutes before sample collection.