MANILA (UPDATE) - Several Senate personnel tested positive for the coronavirus disease 2019 (COVID-19) using rapid test kits hours before the chamber reopened its session on Monday.

As of 3 p.m., at least 14 staff members were found to have antibodies that may be linked with COVID-19, several sources told ABS-CBN News.

By the end of the session, 18 out of the 500 senators and staff members who underwent COVID-19 rapid tests were deemed potential carriers of the virus.

They are among those who were to physically attend the session beginning 3 p.m. and were subjected to mandatory rapid testing.

Two of the 12 who tested positive are staff of senators, 1 is a waiter, 1 is a Senate employee, while the rest are from the Office of the Sergeant at Arms, Senate President Vicente Sotto III said in a statement.

"All 12 [have been] brought to the hospital for swab test and quarantine," he said.

'TOO PRELIMINARY TO PANIC'

Sen. Sherwin Gatchalian confirmed that one of his staff members yielded a positive result from the rapid test.

"The staff tested positive for IgG, meaning she has developed antibodies but we are not sure if the antibodies were caused by COVID-19 because it can be due to cough or colds... So she was taken to a hospital to undergo a swabbing test," Gatchalian told ABS-CBN News.

"Tawag nila rapid test, but it's not really a test. It's a screening device. It screens for the possibility of COVID through your antibodies," he said.

The rapid test, which has a "high false negative" rate, generates 3 results. Negative, IgG or IgM. IgG means you have recovered from a virus, while IgM means "you currently have a virus in your body," the senator said.

"It's too preliminary to panic because hindi mo naman na-detect COVID. The rapid test is an indication that there is a possibility of some staff contracting the virus," he said.

Gatchalian said he and Sen. Ronald "Bato" Dela Rosa both tested negative in the rapid test.

Sen. Panfilo Lacson brought several rapid test kits for senators and staff who would physically attend the session during which a resolution that will allow the Senate to conduct hearings and sessions online will be tackled.

The Philippine Red Cross is expected to conduct confirmatory tests using reverse transcription polymerase chain reaction (RT-PCR) for those who tested positive using the rapid test kits, Senate Majority Leader Juan Miguel Zubiri said.

"We also requested Red Cross na i-test mga senators na gusto magpa-test. So naka-stand by din po ata ang Red Cross," Zubiri said, referring to the organization led by Sen. Richard Gordon.

RT-PCR tests are more accurate than rapid test kits, Health officials have said.

DISCLOSURE

Gatchalian said the Senate should disclose the names of the 12 staff members who tested positive using the rapid test kits.

"Dapat i-disclose sino yung 12. Dapat malaman namin yung 12 na nag-positive because that information will help us decide how to move forward," he said.

Sotto earlier said that he plans to physically attend all the Senate's sessions until the chamber adjourns on June 5, 2020, even if senators are expected to allow online sessions to adhere to the government's policy against large congregations during the pandemic.

The Senate President has yet to respond to queries if the recent development will affect the chamber's subsequent proceedings.

Three senators, including Zubiri, contracted the highly-contagious disease in March before the Senate adjourned on a 2-month break.

Zubiri and Sen. Aquilino Pimentel III have recovered from the disease, while Sen. Sonny Angara again tested positive weeks after his reported recovery.

Four other staff members working for senators Pia Cayetano, Ramon "Bong" Revilla Jr., and Risa Hontiveros also acquired the COVID-19. Revilla's staff succumbed to the disease last month.

- with a report from Tarra Quismundo, ABS-CBN News