Diagnostics
The missing link in point of care diagnostics
Nick Collier highlights the need for innovation in sample collection, to overcome key human factors challenges, and to ultimately improve point of care diagnostics.
Early diagnosis plays a key role in the management of infectious disease, and access to rapid, straightforward, cost-effective testing is central to this capability. Point of Care (PoC) diagnostic devices are widely held as a key enabler. They are a focal point of innovation and with compound annual growth of 10.7%, the PoC diagnostics market is predicted to reach $75.5 billion by 2027.1 This would seem to bode well for improved management of the world’s most deadly and devastating person-to-person infectious diseases, tuberculosis (TB), HIV/AIDS, and viral hepatitis. The spread of other bacterial, viral, and sexually transmitted infections (STIs) could also be controlled more effectively with better access to PoC diagnosis. Low- and middle-income countries, where communicable diseases are a leading cause of death and disability,2
However, an important aspect of successful
PoC diagnosis is often overlooked during innovation. Namely, the collection of samples. Factors such as discomfort, embarrassment, and inconvenience can make patients reluctant to provide a specimen for testing. Furthermore, it can be difficult to obtain samples of sufficient
quality for reliable diagnosis in PoC settings. Improving sample collection for PoC diagnostics could be game-changing for infection prevention. It could also pave the way for further decentralisation, and increased accessibility, of diagnosis at point of need, in community, workplace, or home settings.
could see enormous benefit from this.
PoC diagnostics and infection prevention Eliminating or reducing person-to-person transmission is a central pillar of many infection prevention strategies. A rapid, positive result delivered in a PoC setting while the patient is still present enables prompt treatment. It might also result in the isolation of the patient to minimise the risk of transference in the community. Infected individuals can modify their behaviour to reduce the risk of infecting others too. For instance, somebody who works in a public setting or in a food production role might stay at home until the infection has passed, thereby avoiding wider spread of infection. When measures like these are taken earlier,
fewer people become infected. Replicating this pattern of early detection and intervention at scale can have a significant positive impact on
infection prevention. The benefits can be enormous, especially with contagious diseases that are curable and preventable. Latest World Health Organization (WHO) figures3
show that an estimated 10.6
million people fell ill with TB in 2021, and 1.6 million people died. Cases of drug-resistant TB (DR-TB) increased year-on-year too; a concerning trend which could hinder global TB control. A 2022 report on rapid molecular assays for DR-TB4
highlights the vital role of
rapid diagnostic tests which are “accurate, inexpensive, [and] suitable to be performed on an easily accessible sample”; the goal being to “detect prevalent circulating drug-resistant strains and provide results within a short turnaround time to enable timely treatment initiation”. While progress has been made in the diagnosis of DR-TB, the lack of a simple, reliable PoC test is hindering progress. The report’s authors suggest that ready availability of such a test would bring multiple benefits, including the interruption of transmission. Simple in vitro diagnostic tests that can be performed away from central clinics improve the accessibility of diagnosis, making it easier to engage with people who might not otherwise get tested. So, how can PoC diagnostics be extended to cover more diseases in more parts of the world? The ease with which samples can be collected for analysis is a critical factor. Various specimens can be suitable for PoC diagnosis of infectious diseases, including blood, urine, stool, and genital swabs. Some are perceived as being easier to collect than others, but all can present difficulties.
Human factors Emotional factors such as patient embarrassment or shame can be a barrier to collection, especially for stool samples or genital swabs. Self-collection is now well established as a way to overcome this, and it can be very successful. A study in India looked at the comparative performance of self-collected and physician-collected vaginal swabs for the diagnosis of venereal disease. It established self-collection as a viable alternative tool in the
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