The survey has given us an insight into what is happening globally with RDTs. Many respondents reported 24/7 availability of tests. Very high-income countries had higher proportional availability of rapid influenza and respiratory virus tests. In lower-income countries, however, a lower proportion of respondents reported the availability of these tests, but HIV and hepatitis testing were available in greater proportions. The explanation for this pattern is likely multifactorial. In general, the epidemiology of chronic viral hepatitis and HIV is such that they are more prevalent in developing countries where public health interventions are less likely to identify and treat patients early in the course of illness [7]. The priorities for treatment are also different: influenza management in secondary care is a less pressing need in resource-restricted settings where patient isolation facilities are less readily available. Furthermore, the clinical impact relative to the cost of identifying a case of influenza is less than HIV or viral hepatitis where early identification and treatment make a greater difference [8, 9]. The relative cost of each test is likely to also be a factor in the difference of availability, with multiplexed assays generally being considerably more expensive and requiring more complex logistical support. Methods for reducing the costs of many RDTs are lacking, which limit their availability in low-income settings.
There are still major gaps in capturing the impact of RDTs on decision making in a systematic manner. Only 37% of users measure impact. 64% of those surveyed reported that lack of money was the major barrier to bringing in RDTs in their institution. Developing robust impact recording systems, such as regular audit cycles, coupled with cost-effectiveness analyses are crucial to support business cases for new RDTs.
The current setup of RDTs appears to be more laboratory centred: governance and quality control are the responsibility of laboratories in the vast majority of those surveyed. 90% of those who responded to the survey said tests were carried out in their institution by laboratory staff. Simpler tests lend themselves more towards near-patient deployment and a CLIA waiver is often a good indicator of this. While there are a number of existing international regulatory processes for drugs and medications, providing safeguards for their safety and efficacy, they are often lacking for RDTs [10, 11]. As a result, diagnostic tests are often sold and used in the developing world without any evidence of effectiveness. For example, Mak et al. [12] reported the sensitivity of an RDT for SARS-CoV-2 of 11.1–45.7% when the manufacturer had claimed it was 98%.
The benefit of RDTs can be lost if not coupled with rapid pre- and post-analytical phases. The survey identified that less than half of the results are communicated to the requester directly, and only 35% of reports are generated in real-time on computers. This means delays are introduced as clinicians look up results. Interestingly in some institutions, results are sent out by SMS or email to requesting clinicians which would optimise the reporting process. Identification of certain infectious organisms may have wider public health implications, for example, Legionella; therefore we advocate real-time connection for these results to systems that allow rapid reporting to responsible public health authorities.
A limitation to the method we should consider is the selection bias towards ISAC members who would be motivated to respond to the survey: potentially those who have the greatest interest in RDTs or who are highly critical of them. There is also a bias towards respondents with greater resources suggested by the fact that at least 90% of tests had a laboratory involvement. Furthermore, the survey size is relatively small and certain world regions (especially Southeast Asian nations and Sub-Saharan African nations) are poorly represented.
The main aims of RDTs are to improve patient care most efficiently within well-managed healthcare systems. We therefore suggest a number of best practices for implementation of RDTs (Table 1).
Table 1 Best practices for RDT implementationFull size table
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