No other Singapore lab using COVID-19 test kit that led to 33 false positive cases

SINGAPORE (CNA) – Other laboratories are not using the same COVID-19 test kit and analytical instrument combination as a lab that had 33 “false positive” cases, the Ministry of Health (MoH) said.

Thirty-three previously confirmed COVID-19 cases, including a radiographer who worked at the Singapore Expo community care facility, had turned out to be negative cases upon retesting by the National Public Health Laboratory.

This was due to an “apparatus calibration issue” for one of the test kits used between May 5 and May 9, MoH said on Wednesday in response to CNA’s queries.

“MoH has since reviewed the test results of the affected batches, and there were no false-negative results discovered from the review,” the Health Ministry added.

None of the 12 other laboratories conducting COVID-19 tests is using the same test kit and analytical instrument combination, MoH told CNA.

A medical worker performs a nose swab test on a migrant worker at a dormitory amid the COVID-19 outbreak in Singapore. PHOTO: CNA

“The laboratory has switched to another test kit that has been proven to work on the analytical instrument,” the Health Ministry said. The 33 cases had been isolated after they were “assumed to have COVID-19”, and will be “further tested as necessary”, MoH added.

A large majority of COVID-19 tests in Singapore are conducted by the National Public Health Laboratory and public acute hospitals, supported by various private laboratories, the ministry noted.

“MoH regularly audits the test results of these laboratories. Laboratory test results are also checked against the patients’ clinical signs and symptoms,” it said.

The health ministry also reported last Sunday that two people from the public healthcare sector who worked at the Singapore Expo community care facility had “equivocal” results.

Their results were also sent to the National Public Health Laboratory for retesting, and they came back negative.