How the test for coronavirus works
THE company that performed coronavirus testing for Australians on Christmas Island has revealed how the process works.
AusDiagnostics managing director Keith Stanley told news.com.au the company sent equipment and samples of the coronavirus to Christmas Island to test the Wuhan evacuees for COVID-19.
A member of their company also volunteered to travel to the island to perform the tests as they would also need to be quarantined for two weeks.
Mr Stanley said testing for all viruses including COVID-19 used swabs taken from the throat or nose because the virus is found in mucus in the membranes.
"That's why when you sneeze or blow your nose, you are actually shedding a lot of virus and it's where contagion is most at risk," he said.
Testing for coronavirus involves testing people's DNA to find a specific sequence unique to COVID-19.
AusDiagnostics use a polymerase chain reaction machine to test people's swabs and it usually takes about three hours for a result.
Mr Stanley said the process only uses tiny parts of the virus for comparison and so the samples are not infectious.
COVID-19 was first sequenced in China and its details are available through public databases.
Since the coronavirus has ribonucleic acid (RNA) as its genetic material, this is converted to DNA for comparison purposes.
Mr Stanley said they actually test for two parts of the sequence so if the virus mutates in one part of the DNA, they are still able to identify it using another part of the sequence.
Samples from about 130 cases of the virus have so far been sequenced and having more samples is important because it helps scientists to identify mutations.
Once a result was known, Mr Stanley said they also sent the material to Sydney's Westmead Hospital for testing to confirm their results.
After spending two weeks on Christmas Island, all 241 Australians evacuated from China in February were cleared of coronavirus.
Mr Stanley said those on Christmas Island were only tested if they showed symptoms as a decision was made not to panic people unnecessarily.
The testing is similar to that used for detecting disease like HIV, Hepatitis B and C, and the common cold.
However, it's different from antibody testing, which is a blood test that can reveal whether someone has been infected by the coronavirus even if they have not shown any symptoms.
There is currently no antibody test available in Australia and experts believe it may take another couple of months to develop.
The number of coronavirus cases in NSW has more than doubled in a week with 29 cases now detected.
Epping Boys High School was closed on Friday as a precautionary measure after a Year 11 student tested positive.
Across Australia there have been 63 cases and authorities have advised people who are unwell to stay at home.
"Make sure you self-isolate if you feel you've got any symptoms, stay at home if you're unwell, follow the basic procedures and at all times know that our health system is on high alert," NSW Gladys Berejiklian said.
"We are anticipating this virus will have a concerning phase of a number of months ahead of us."
The NSW chief health officer says people should be careful when visiting hospitals to avoid potentially infecting vulnerable patients.
"If you have any symptoms of an illness, albeit incredibly mild please, defer visits," Dr Kerry Chant said.
Healthy people visiting hospitals should wash their hands thoroughly prior to and after entering wards.