New position statement on COVID-19 Antigen and Point of Care Testing
This month, the RCPA released a new position statement on COVID-19 Antigen and Point of Care Testing (POCT). The new position statement recognises Australia’s changed circumstances to having a high prevalence of COVID-19 infections after the Omicron surge, and the approval of self-testing (home use) by the Therapeutic Goods Administration (TGA). Dr Lawrie Bott, President of the RCPA explains what’s changed.
“The RCPA continues to recommend PCR testing, which is highly-sensitive and specific, for people with symptoms and in certain high-risk situations. RAT testing can be used in selected scenarios (principally the surveillance of asymptomatic individuals), however the significant loss of sensitivity compared to PCR testing should be noted. False negatives could be as high as 4 in 10 in COVID-19 RAT users who are asymptomatic but do have COVID-19 and would test positive with a PCR test.
“At the present high prevalence stage of the pandemic in Australia and New Zealand, RATs have an important place supporting PCR tests in surveillance, monitoring and diagnosis of COVID-19 infections. Suggested absolute indications for PCR diagnosis are provided in the updated position statement,” said Dr Bott.
The RCPA has previously released three position statements about RATs. The latest statement addresses: the potential indications for RATs now that SARS-CoV-2 is highly-prevalent in Australia and becoming so in New Zealand, the inherent limitations of RATs; and the suggested circumstances where RAT results should be confirmed by PCR tests.
“One major risk of self-testing (home use) is the potential loss of epidemiological information about the number of COVID-19 tests performed and the results. The College therefore strongly supports the establishment of electronic online RAT notification systems, for both positive and negative results, to maintain this vital flow of data. The RCPA also notes and agrees with the requirements for point-of-care testing (POCT) described on the TGA website.
“In addition, RATs should have independent laboratory-based and clinical assessment of their performance to guide the use of these tests, particularly with new variants. Ideally, these assessments should be performed both pre- and post-market release.
“The capacity for swab collection and PCR testing was overwhelmed in Australia during the Omicron surge and because of other factors in late 2021-early 2022, which along with testing requirements for domestic and international travel, caused delays. In these circumstances, RATs have provided an adjunctive diagnostic method for testing asymptomatic and symptomatic patients. Ideally all symptomatic, and high-risk patients, even in a surge situation, would be investigated by PCR testing. If this ideal is not feasible, PCR testing should be targeted toward certain high-risk or sentinel populations, as outlined in our position statement.”
Unlike in many other high-income countries (including the US and UK), laboratories in Australia and New Zealand have maintained a high-testing capacity with acceptable turnaround times (TATs) through the first two years of the pandemic. Over 60.4 million SARS-CoV-2 PCR tests have been performed in Australia since the pandemic began, with over 1 million tests being performed between 19-26 January 2022, demonstrating that PCR testing capacity has been restored and symptomatic patients can again benefit from the optimal diagnostic test.
The College recommends that RAT-positive results require a confirmatory PCR in the following circumstances:
RAT-positive patients eligible for monoclonal antibody or other antiviral therapies (to avoid unnecessary treatment & adverse reactions);
RAT-positive pregnant woman;
Initial index case in a nursing home, disability, prison, remote-community outbreak to confirm outbreak before triggering an outbreak response;
Any symptomatic RAT-positive patient admitted to hospital to confirm diagnosis (particularly before being in a room/cohorting with other COVID-19-positive patients);
RAT-positive critical worker (e.g. a healthcare worker) to confirm the need for furlough and ensure appropriate future infection control measures.
In conclusion, the RCPA highlights the lower sensitivity and specificity of RATs, which ideally should not be used alone for diagnostic purposes. Authorities may need to use RATs for surveillance purposes in circumscribed agreed settings, in COVID-19 hotspots and surges, and regrettably for diagnosis if timely PCR testing is not available during a large surge. Absolute indications for PCR diagnosis have been provided.
RCPA Fellows are contributing to RAT selection and other deliberations to optimise the implementation of RAT testing in the Australian and New Zealand contexts.
