POINT-OF-CARE TESTING


correct pathways in certain areas and for certain clinical groups of patients, highlighting respiratory virus testing in central laboratories as a bottleneck to rapid care. Diagnostic test providers were able to respond quickly to this demand, and POC PCR testing systems became a godsend during the COVID-19 pandemic.


The cost of misdiagnosis In emergency departments, prompt and accurate diagnostics for SARS- CoV-2, influenza A and B, and RSV are crucial for determining the right clinical management and treatment plans for patients. Rapid antigen tests have been used to detect each of these viruses, but there is not a solution that combines all four, requiring multiple antigen tests to be performed. For COVID-19,8


these


rapid antigen tests lack sensitivity and accuracy in early and late stages of the infection timeline,9


are described as having only moderate sensitivity (50-70%),10 room for errors.


Misdiagnosis can have serious


repercussions, including ineffective treatments that may worsen symptoms or even advance the disease. The clinical repercussions of a wrong or delayed diagnosis must be taken into consideration in the economics of choosing a POC testing solution for respiratory viruses. PCR testing offers high sensitivity and specificity, providing clinical staff with a wider investigative window, meaning it is more likely to result in a correct diagnosis for these patients. Establishing a POC PCR testing pathway may be perceived as more expensive than using traditional laboratory testing; however, the initial outlay can in fact be offset against clear cost savings to the organisation as a whole – from improved workflows, quicker discharge, reduced bed blocking, and workforce and patient protection against hospital-acquired infections11


– and the benefits have been shown to outweigh the cost.12


Developing world-class assays Introducing PCR at the point of patient care has the power to transform traditional healthcare models to better meet patient needs, helping to flow them through the system with results


and for influenza, they potentially leaving


In addition to providing accurate multiplex testing, POC instruments must be suitable for use outside traditional laboratory settings. POC testing can be deployed wherever it is most convenient for the patient


that are accurate and reliable. However, just like the respiratory viruses, the world of diagnostics doesn’t stand still; it is important that diagnostic companies continue to refine and adapt their molecular systems to respond to the ever-evolving disease landscapes. Many POC PCR technologies have been designed to improve the convenience and efficiency of patient care pathways, with the aim of minimising delays and enhancing overall care outside traditional hospital settings. A POC device must be sensitive, specific and reliable without requiring additional reflex tests, especially when time is critical, to be considered a viable alternative to centralised testing.


Multiplexed PCR assays such as the


but with the added benefit of simultaneous testing. The test has been designed to amplify and detect unique sequences in three SARS-CoV-2, three influenza A, two influenza B and two RSV genes, helping to avoid the chance of variants evading detection. Covering an extremely broad range of genetic variation without compromising accuracy helps to reduce false-negative results and ensure the test continues to be effective in future seasons as the viruses evolve.


The clinical repercussions of a wrong or delayed diagnosis must be taken into consideration in the economics of choosing a POC testing solution for respiratory viruses


26


Xpert Xpress CoV-2/Flu/RSV plus from Cepheid represent an ideal solution for addressing the overwhelming demand for respiratory diagnostics in record time. This innovative test offers an holistic approach by enabling the simultaneous detection of multiple pathogens from a single sample, simplifying the diagnostic procedure and removing the need for multiple swabs. Multiplexed PCR assays for SARS-CoV-2, influenza A and B, and RSV have been shown to be highly sensitive and accurate in POC settings, with a comparable performance to individual tests for each virus,13


Intuitive hardware for ease of use In addition to providing accurate multiplex testing, POC instruments must be suitable for use outside traditional laboratory settings. POC testing can be deployed wherever it is most convenient for the patient, and during the COVID-19 pandemic instruments were often set up in small, adjacent rooms next to an emergency department. Out of necessity, the hardware must be compact and seamlessly fit into any location. However, they must still be user friendly, enabling those without experience of PCR testing to quickly and easily understand how to set up a protocol and interpret the findings with results that are easy to visualise. This was particularly important during the COVID-19 pandemic when staff resourcing was limited, and some departments were faced with one POC testing assigned person on shift, who was unlikely to be laboratory experienced. Instigating PCR testing adds an additional responsibility to these frontline healthcare workers, so must be a continuous adjunct to their existing roles with straightforward operation. Connectivity between different systems within a hospital and across sites also adds another essential component to instruments, enabling decentralised POC PCR testing with greater control and standardisation of the operating parameters to retain the quality of care.


Systems with a user-friendly integral


touchscreen such as the GeneXpert system are more compact, eliminating the need for a laptop that would occupy additional bench space, and making them easier to implement wherever they are needed. The intuitive and easy- to-use touchscreen sits on top of the system, allowing users to visualise the results – including Ct and PCR curves – and providing an ideal solution for those with little experience of operating PCR testing to quickly learn how to run protocols. Connectivity between systems in the same hospital and across different sites streamlines the diagnostic testing process closer to the patient while maintaining laboratory standard testing


DECEMBER 2024 WWW.PATHOLOGYINPRACTICE.COM


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