When undergoing nucleic acid testing for COVID-19 virus, people have an option of providing either a nasal swab sample or a throat swab sample. As of 20 May 2020, the Government’s Public Health Laboratory has in aggregate analysed more than 50,000 samples of human nucleic acid for such testing.

A Public Health Laboratory staff member cross-checks a test subject’s information and the identifying tag on a sample bottle. A team of 30 at the Public Health Laboratory is being tasked with the testing work. The extended working hours of the Public Health Laboratory are now 8am to 10pm, in order to handle a daily average of 1,000 samples for nucleic acid testing.

A laboratory technician in full protective gear deals with nucleic acid samples before a further analysis process.

The laboratory technician puts samples in a ‘lysis buffer’ – a special type of solution – to extract nucleic acid and at the same time inactivate any virus that might be present.

The samples are then placed in a centrifuge, with the machine set at low speed in order to avoid aerosols being generated from the samples.

Inactivated samples are placed in a machine for automated extraction of nucleic acid.

A laboratory technician mixes reagent with nucleic acid extracted from the samples.

The resulting mixture is then placed in a nucleic acid detection machine to detect the particular nucleic acid sequence of the COVID-19 virus, via a technique using fluorescence.

When the machine detects fluorescent signal from nucleic acid samples, it means that the result is positive for COVID-19 virus; otherwise, it is negative.

Upon reception of samples, the Public Health Laboratory takes about three to four hours to run the entire analysis process.