Dr Lyn Waring is Chair of the Royal College of Pathologists of Australasia’s (RCPA) Microbiology Advisory Committee and has been integrally involved in the pathology testing for COVID-19 in Australia. This month, Doctor Waring answers questions on testing for COVID-19.

How accurate is the COVID-19 test?

The current tests being used in Australia are the Polymerase Chain Reaction (PCR) tests, which are a type of incredibly sensitive and specific molecular tests. The true positive and negative rate in any population, depends on the selection of the population tested and the quality of the samples.

Currently, we have largely concentrated on testing individuals who have returned from countries with COVID-19, who present with symptoms of the infection. We have not tested individuals from the broader community, which would be required to understand the true positive rate of infection in our community.

Are laboratories coping with the demand?

Laboratories are working around the clock to effectively deliver high-quality testing within short timeframes as they test for and diagnose COVID-19. Pathologists are doing everything they can to minimise delays in getting results getting back to patients, including streamlining processes and working 24/7. As the numbers of cases increase in our community and therefore the number requiring testing there will be greater pressure placed on pathology laboratories.

There has been a huge influx of testing, however, laboratories are doing everything possible to minimise delays. Dedicated laboratory staff, couriers and collectors are all working hard to ensure that laboratories have the support needed for this public health emergency. One of the most important factors is to ensure the health of the staff in the laboratories, as there are only a finite number of appropriately trained staff to do this work.

Are blood tests being used for COVID-19 in Australia?

A number of serology and point of Care (POCT)Antigen, IgM/A and or G tests have recently been released into the market in Australia. However, these IgG/IgM tests have a fundamental limitation; they rely on the detection of antibodies made by the patient in response to SARS-COV-2, they do not detect the virus. Patients may only make antibodies to COVID-19 infection a week to 12 days after they first become sick, therefore, if doctors rely on these rapid tests early in the disease, their diagnosis will be wrong.

The RCPA therefore supports the use of molecular tests for SARS-COV-2 and advises against the use of serological COVID-19 IgG/IgM rapid tests, such as a pin prick blood test, to detect early COVID disease. Whilst these new antibody tests may have a place in detecting unrecognised past infection and immunity, that role still needs to be rigorously evaluated.

What kind of equipment do you need?

The machines are highly specialised, however there is a large range of them. Some can be quite large and expensive, and they differ in terms of availability, capacity and speed, and their ability to transfer results into the laboratory computer system.

Is there a problem with reagent shortages?

At present, the Federal Government has been able to source additional test kits for many of the required reagents.

The Royal College of Pathologists of Australasia (RCPA) endorses the strict use of the Communicable Diseases Network Australia (CDNA) National Guidelines when deciding whether to refer a patient for a COVID-19 pathology test. This approach will assist in the effective management of increased demands on pathologists and laboratories, ensuring that resources are allocated appropriately.

The guidelines for COVID-19 testing have been endorsed by the Australian Health Protection Principal Committee and recommend testing only where a patient meets both the current epidemiological and clinical criteria.

Are we able to scale up activities in Australia?

There were no tests for this newly discovered virus in late January, therefore it is incredible that there are now commercial kits available for wide use by the global population. This is as a vital part of incubating this pandemic. Laboratories have had to upscale on a large scale already, from doing no tests to up to over 1,000 per day, in some cases.

Turn-around times for pathology tests can vary between laboratories and there are two groups of factors to consider. Firstly, there are the factors within each laboratory which can include, workloads, testing methods and staffing levels. Secondly, particularly in a country as sparsely populated as Australia, are those factors outside the laboratory. These include factors, such as, the time taken between specimen collection and delivery of the specimen to the laboratory for testing. Additionally, the overall large volume of testing will also have an impact on turn-around times in both of these areas.