The Government today announced that the evaluation criteria for COVID-19 nucleic acid test results will be adjusted with effect from January 16, under which test results with a cycle threshold (Ct) value of 35 or above will be regarded as negative.

In view of the epidemic development and the fact that cases with a COVID-19 nucleic acid test result at a Ct value of 35 or above are generally not associated with infectiousness, the Centre for Health Protection (CHP) assessed the relevant risks and decided that people with nucleic acid test results at a Ct value of 35 or above will not be regarded as confirmed cases starting January 16 and thus they will not be issued with isolation orders.

From that day, all local COVID-19 reverse transcription polymerase chain reaction testing institutions recognised by the Government, including community testing centres or stations in various districts, will classify all those nucleic acid test results with a Ct value of 35 or above as negative for purposes other than clinical management.

All test results issued since January 16 will adopt the adjusted evaluation criteria, regardless of whether the specimen collection was carried out on or before that day.

The adjusted criteria also apply to free and self-paid tests conducted by community testing centres or stations, and the self-paid negative test reports can be used for cross-boundary travelling purposes.

For people who tested positive before January 16 by nucleic acid tests with a Ct value of 35 or above and are still holding isolation orders that are in force, the CHP will notify them by SMS before noon on January 16 that they are no longer required to undergo isolation and their isolation orders are cancelled.

The Government will also arrange relevant people in isolation facilities to discharge in an orderly manner.

Separately, as there is no Ct value for rapid antigen tests (RATs) which have a lower sensitivity than nucleic acid tests, a positive RAT result indicates a higher viral load. Hence, patients with positive RAT results reported via the Declaration System for Individuals Tested Positive for COVID-19 Using Rapid Antigen Test will not be affected and they should continue to be isolated according to the conditions originally stipulated in their isolation orders.

The Government also reminded people that they may conduct self-paid tests at accredited medical testing institutions to obtain test reports for travelling purposes.

Currently, people going to the Mainland from Hong Kong must hold a negative result of a self-paid nucleic acid test. If their test result is positive with a Ct value below 35, they cannot enter the Mainland.