Scientists are calling for random blood testing to track the spread of COVID-19 and help in the fight for treatment, as cases continue to climb in Australia.

Key points: Blood testing could help researchers learn about exposure and develop coronavirus antibodies

Blood testing could help researchers learn about exposure and develop coronavirus antibodies The controversial practice has already attracted international attention, but diagnostic testing is expensive

The controversial practice has already attracted international attention, but diagnostic testing is expensive Days-long delays in COVID-19 testing has raised concerns for the risk of community transmission

The majority of testing for coronavirus is conducted by using respiratory tract swabs, where samples are taken from a patient's nose.

Depending on testing capabilities, the results can take days to return.

There are growing calls in Australia to introduce serological testing — a diagnostic blood test.

The test would help health officials know if people have been exposed and developed antibodies against the virus.

"The current PCR test only tells you whether a person has the virus at this moment," Dr Meru Sheel, an epidemiologist and research fellow at the Australian National University said.

"What it doesn't tell you is that a person may have had the infection, has recovered and is immune or not immune."

Dr Sheel said a serological test would help understand at population level how many people have been exposed to the disease, have recovered and if there are populations that are not immune to the virus.

"It's an important tool that's been brought up nationally and internationally," she said.

It could also uncover missing links between confirmed clusters of the virus.

The tests have been introduced in other countries like Singapore, the US and China, but so far, they are not available in Australia.

Professor Peter McIntyre, from the University of Sydney, said this was partly because Australia did not have a national health body to coordinate disease research.

"You're dealing with states and territories and a Federal Government, which is why these things are very hard to get off the ground," he said.

"If you had a national coordinating body then sero-surveillance might be one of many activities which they would coordinate a national approach to."

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Emeritus Professor John Dwyer, an immunologist at the University of NSW, said mass testing could take place at GPs or schools.

"It would be done by researchers who would design specific clusters," he said.

"For example you might take five very different GP practices and for those practices anyone who has any respiratory symptoms you would test them."

Emeritus Professor Dwyer, who took a leading role in the campaign to combat the spread of HIV and AIDS, said the cost of research would be expensive but the results would be crucial.

"We might get a horrible shock when we find the number of cases is multiplying much faster than we thought it would because we didn't realise how many people in the community were carrying the virus," he said.

"You have to ask yourself — if other countries are doing it and getting valuable information is this something Australia should do as well?"

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Professor McIntyre said diagnostic testing would be a "nice to have" but not essential.

"I think if you wanted it to happen it would make sense to be planning for it and it's likely it would be beneficial in the future," he said.

"But when this whole COVID-19 experience is being looked back on and we say 'what went right and what went wrong', then having this information is important."