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COVID-19 serology point-of-care tests
Point-of-care COVID-19 serology tests detect human antibodies produced in the days after a person is infected with the SARS-CoV-2 virus. These tests are usually presented in a small plastic cartridge, similar to pregnancy tests, and require a blood specimen for testing.
There is significant variation in how point-of-care testing is being used across Australia in response to the COVID-19 pandemic. Western Australia, South Australia and Queensland have introduced certain prohibitions or restrictions on the use of point-of-care tests.
Currently, a number of COVID-19 point-of-care tests have been approved by the Therapeutic Goods Administration (TGA) subject to conditions, including restrictions on who can obtain them. The TGA is conducting a post-market review of all approved serology point-of-care COVID-19 tests to verify their performance and inform their best use. The Department of Health has engaged the Peter Doherty Institute to assist in the post-market validation of these tests.
We urge everyone who is considering offering a COVID-19 point-of-care testing service to read the following information.
- Serology point-of-care COVID-19 tests cannot determine whether a person is infectious.
- Serology point-of-care COVID-19 tests are not able to detect if a person has been recently infected.
- Management of an effective COVID-19 response relies on accurate reporting of COVID-19 infections from all facilities that offer testing.
- It is illegal to supply or advertise these COVID-19 point-of-care tests as self-tests or tests for home in Australia.
Offering point-of-care serology services
There is widespread interest in the use of point-of-care serology tests to increase testing capacity for COVID-19 in Australia. Because the accuracy and reliability of COVID-19 testing is critical during this time, we strongly urge potential providers of testing services to consider their capabilities and the context of providing testing services before commencing the provision of any COVID-19 point-of-care testing service.
It is important to note that COVID-19 point-of-care tests cannot be advertised to consumers. There are also obligations for any advertisements directed to health professionals.
A significant risk in point-of-care testing relates to misinterpretation of the result. Accurate identification of a COVID-19 infection based on serology results requires an understanding of how the antibody response develops with time, and how there is a significant lag time between infection and the development of antibodies. All point-of-care serology tests currently available in Australia detect IgM and/or IgG antibodies that develop in response to an infection with the SARS-CoV-2 virus. These tests do not detect the SARS-CoV-2 virus itself. This is important because, while these tests can detect if a person has been exposed to the SARS-CoV-2 virus, they cannot determine whether a person is currently infectious or has recently been infected with the virus.
Positive point-of-care serology result
A positive IgM and/or IgG serology result indicates that a person has been exposed to the SARS-CoV-2 virus. It is possible that the person has a current COVID-19 infection and is potentially infectious. In a symptomatic person, a positive result may be sufficient to presume infection with COVID-19 but this should be confirmed by laboratory testing. Current Communicable Diseases Network Australia guidelines for further testing and self-isolation should be followed.
Negative point-of-care serology result
It can take up to two weeks, or even longer, for point-of-care serology tests to detect antibodies that are produced in response to a viral infection. These timeframes are still being confirmed. It is recommended that serology point-of-care COVID-19 tests should not be used until at least two weeks post onset of symptoms. Therefore a negative IgM and/or IgG serology result cannot rule out a current COVID-19 infection. This is particularly true if a patient has no symptoms, or has had symptoms for less than two weeks.
Note: The ability of serology tests to accurately detect exposure to the SARS-CoV-2 relies on their sensitivity and specificity, which can vary significantly between different assays. Serology tests can be cross-reactive and detect antibodies produced in other infections. For example, less severe seasonal coronaviruses circulating in the community can induce antibodies that cross-react in a COVID-19 test to produce false-positive results. Serology tests can also fail to detect COVID-19 if testing is performed in the acute phase of the infection prior to the development of detectable antibodies.
Serology testing is generally used in epidemics to aid in the investigation of the outbreak to better understand the rate and pattern of infection. This relies on the serology point-of-care test results being captured by public health reporting networks. Serology testing may also be useful if SARS-CoV-2 nucleic acid tests are repeatedly negative, but the patient's symptoms and epidemiology are strongly suggestive of infection with COVID-19. However, such complex cases should be referred to a specialist infectious disease physician for further investigation.
Point-of-care testing considerations
There are a number of issues that require particular consideration for any point-of-care testing services. These include:
- potential for misidentification of the patient and/or test specimen
- infection risk for the patient and the operator
- inadequate record keeping for patients and products used.
Blood specimens collected for point-of-care testing, as for other forms of testing, should be regarded as potentially infectious not just for SARS-CoV-2, but also for other blood-borne infectious diseases. Staff must be trained in appropriate specimen collection and infection control.
If you are intending to offer point-of-care COVID-19 testing, staff in your facility should have the knowledge, experience and capabilities to safely and accurately carry out the specimen collection and testing, correctly interpret the results, provide current and correct health advice based on these results, and have robust record keeping and reporting systems in place. The National Pathology Accreditation Advisory Council has published guidance on key considerations for COVID-19 point-of-care testing used in health care settings.
- Please see the TGA website for information on the legal supply of point-of-care COVID-19 serology tests.
- Please see the Department of Health website for all COVID-19 updates.