DOH assures Zubiri of COVID-19 testing accuracy after another virus scare


Posted at Jul 29 2020 07:16 PM | Updated as of Aug 12 2020 03:39 PM

DOH assures Zubiri of COVID-19 testing accuracy after another virus scare 1
Senate Majority Leader Juan Miguel Zubiri. Henzberg Austria, Senate PRIB

MANILA — The Department of Health on Wednesday addressed concerns of Senate Majority Leader Juan Miguel Zubiri after he tested positive again for COVID-19 and then tested negative in a confirmatory test.

In a privilege speech on Tuesday, Zubiri, a COVID-19 survivor, questioned the accuracy of the test he took as a requirement to attend the State of the Nation Address on Monday. The test was done by a GeneXpert machine, which could process COVID-19 tests faster than the regular polymerase chain reaction (PCR) test.

“I'm not quite sure of the sensitivity of these machines, if they can distinguish dead or live ones,” he said, pointing out that the machines were intended for tuberculosis samples.

He then said that he prefers the machine used by the Philippine Red Cross, which processed his confirmatory test that turned out negative.

Health Undersecretary Maria Rosario said on Wednesday that the PCR test in general is accurate.

“We reiterate that the polymerase chain reaction (PCR) is very sensitive and can detect the virus and/or virus genetic materials/remnants,” she said during a televised briefing.

Vergeire explained that because of the test’s sensitivity, it might have detected remnants of the virus from the samples of the senator, who first tested positive for COVID-19 in March. She said there have been evidence showing how patients could remain “PCR positive for many weeks, or even test PCR positive after days/weeks of a negative test.”

She said the senator’s positive test result before the SONA might not indicate a true infection. The health official also admitted that the test could be a false positive due to cross-contamination.

“Nais po naming i-emphasize na ang GeneXpert machine po ay isa rin pong klase ng PCR machine o PCR test,” she added.

(We also want to emphasize that the GeneXpert machine is also a kind of PCR machine or PCR test.)

The GeneXpert machine, while made to run tuberculosis diagnosis, has been approved to run PCR tests. Because it uses cartridges, it is faster than the regular PCR machines. The utilization of GeneXpert machines in laboratories nationwide had helped increase the testing capacity of the country.

Zubiri also asked the DOH to “come out with the right protocols dealing with recovered patients, so they won't be discriminated against in the future.”

Asked if recovered or asymptomatic patients should be required to take another PCR test, Vergeire said it is not needed.

She said DOH’s Department Memorandum No. 2020-0258 or Updated Interim Guidelines on Expanded Testing for COVID-19, released on May 29, already states that COVID-19 patients do not need repeat testing to be discharged from the hospital.

“They can be released based on a clinical assessment of a licensed physician,” she said. 

“Para naman sa mga pasyenteng nag-test ng positive sa RT-PCR at wala pong sintomas for at least 14 days, maaari na pong itigil ang quarantine at tawaging recovered kahit walang repeat test basta may clearance na po sila galing sa kanilang doctor,” Vergeire added.

(For patients who tested positive through the RT-PCR and do not have symptoms for at least 14 days, they can end their quarantine and be called recovered without a repeat test as long as they have a clearance from their doctor.)

“Pinaaalalahanan po namin ang publiko na lagi pong kumonsulta sa doktor para po buo ang clinical picture at may saysay ang pagpapa-test po natin,” she said.

(We would like to remind the public to always consult a doctor to see their full clinical picture and so that our test would serve a purpose.)

She assured the public that the DOH continues to consult with experts to ensure that their guidelines are up to date and based on scientific evidence.

Because of the virus scare, Zubiri ended up taking 3 rapid tests and 2 PCR tests in less than 24 hours before he was declared negative of COVID-19.

Asked how long the turnaround time was for PCR tests, Vergeire said it was 48 to 56 hours and 24 to 27 hours for GeneXpert machines.