Testing, diagnosis, and treatment following the implementation of a program to provide dried blood spot testing for HIV and hepatitis C infections: the NSW DBS Pilot

Stopping HIV transmission and eliminating hepatitis C virus (HCV) infection are key aims of global and national health strategies [1‐3]. Home-based self-testing improves HIV testing uptake [4] and dried blood spot (DBS) sampling improves HCV testing uptake [5]. Few studies have evaluated the large-scale implementation of DBS as a strategy to improve HIV and HCV testing uptake among key populations.

Traditional testing pathways for HIV and HCV can be complex and involve multiple visits which may delay diagnosis and access to care or increase loss to follow-up [6‐8]. For HCV, the traditional testing pathway involves an HCV antibody test to confirm exposure and, among people who are HCV antibody positive, an HCV RNA test to detect current infection. This two-step pathway often requires multiple visits to practitioners and off-site phlebotomists, leading to many people who are HCV antibody-positive never receiving confirmatory HCV RNA testing and thus linkage to care [9, 10]. For people who have a long history of injecting drug use, poor venous access can pose challenges for sample collection [11], leading to negative experiences of blood sample collection which may present a barrier for future HIV and HCV testing [11].

DBS sampling enables home self-collection or assisted collection at trusted services and requires minimal resources for collecting, storing and transporting blood specimens, making it suitable in many settings [12]. Fingerstick samples reduce the need for venepuncture, making it more accessible for people with poor venous access [13]. DBS testing has been shown to improve HCV testing uptake compared to standard of care [5, 14, 15] but may be inferior to rapid point-of-care testing in terms of treatment initiation [16, 17]. Large-scale evaluations of DBS testing programs are critical to understand feasibility, acceptability, and impact to inform health service planning.

The RE-AIM framework has been developed to facilitate research translation into practice [18]. The framework uses five dimensions to understand the public health benefit of an intervention, including those at an individual level (Reach, Effectiveness, and Maintenance) and staff/setting levels (Adoption, Implementation, Maintenance) [18]. The framework can be applied flexibly and adapted to the available evaluation resources through “pragmatic use of key dimensions rather than comprehensive applications of all elements” [18] and in this study we report on four dimensions. This study used the RE-AIM framework to evaluate the reach, effectiveness, adoption, and implementation of DBS sampling for HIV and HCV testing in New South Wales, Australia.

This study applied the RE-AIM framework to evaluate the reach, effectiveness, adoption, and implementation of a state-wide program to enhance HIV and HCV testing through DBS sample collection in New South Wales, Australia. DBS facilitated increased reach of testing, particularly for certain sub-groups such as those who had not recently tested. Testing for HIV via online self-registration had high uptake among MSM and people born overseas. Assisted registration with DBS was shown to be valuable in detecting current HCV infection in both the community and prison settings, particularly among people who inject drugs. Minimal operator training and its suitability for use outside of clinical settings means that DBS for HIV and HCV testing is a useful tool in the home, community, and prison.

The overall HIV prevalence (0.1%) is lower than that among gay and bisexual men attending publicly funded sexual health clinics and private GP clinics with high caseloads of gay and bisexual men in NSW (0.5% in 2022 [24]). The online self-registration pathway was most successful at testing key populations for HIV, including MSM (65%) and people born overseas (45%). This is similar to data from public sexual health clinics in NSW in 2022, where 62% of HIV tests were performed among MSM and 41% among people born overseas [24]. It is encouraging that 80% of people with an HIV diagnosis initiated treatment within six months. Although HIV prevalence was lower compared to that found when testing in other services, using DBS in online self-registration may extend the reach of HIV testing to populations who do not regularly attend services and are less engaged in care.

Overall, the proportion of people participating in the NSW DBS Pilot who live outside of major cities (21%) is less than the proportion of all people tested for HCV RNA in NSW who live in rural/regional areas (44%) [25]. Nonetheless, DBS allows people to collect a sample at home or with a clinic on outreach so it may improve uptake among people who are not otherwise able to access a clinic where HCV RNA testing is offered. In the assisted registration pathways, the prevalence of current HCV infection was 17% in community and 14% in prison. This is comparable to Australian studies among people who inject drugs attending drug treatment and needle and syringe programs (17%, 2019–2021) [26] and people in prison (19%, 2014–2019) [27]. The NSW DBS Pilot reached similar populations to Australian studies of HCV but may improve the capacity of sites that do not have access to point-of-care testing, by allowing them to test for HCV with limited resources. Of all HCV treatment initiations in New South Wales for the period 2017–2020 (n = 19,351) [28], 2% were diagnosed in the NSW DBS Pilot. The model of high intensity testing campaigns in prison, where large numbers of people can be tested in the yard or other shared space, shows the potential for scale up of DBS in under-resourced settings.

Half of MSM tested for HIV reported no HIV test in the two years prior to enrolment, higher than a survey of MSM in Sydney in 2022 (38% with no HIV test in the last year [29]) and higher than community-based testing sites in 2019 (15% with no HIV test in the last year [30]), demonstrating that the Pilot outperforms other HIV testing strategies to reach people testing less frequently. In a 2016 survey of culturally and linguistically diverse populations in NSW, 80% reported no HIV test in the last year [31] compared to 62% reporting no HIV test in the two years prior to enrolment in the NSW DBS Pilot. Given that the pilot has been successful in reaching people who have not recently tested for HIV, there is an opportunity to sustain engagement with these populations by incorporating evidence-based complementary interventions such as text message reminders [32].

Forty-five percent of all participants reported not having received HCV testing in the two years prior to enrolment. Among people who inject drugs, 32% reported not having received recent HCV testing, lower than a national survey of people who inject drugs (57%) [33], suggesting that the NSW DBS Pilot may be reaching a population of people who inject drugs better linked to healthcare. Promotion of the online self-registration pathway targeted mainly MSM but further investigation is needed to understand how this pathway could enhance HCV testing for other populations.

Although there were 36 community sites participating in the pilot, the median number of tests per site per year enrolled varied widely (IQR 5–46). Further research is needed to identify enablers for testing in sites demonstrating higher testing numbers. The median time from sample collection to arrival in lab was similar across all registration pathways (6–7 days). Reducing the time from collection to arrival in the laboratory could reduce the time to the delivery of results and improve linkage to care, particularly in the community pathway. After the introduction of the visual aid to assist with sample collection, 90% of cards had the three full spots required to process, comparable with an online postal DBS testing project for STIs in England which reported 95% of cards successful processed [34]. The visual aid is an important element in the implementation of any DBS program which requires self-collection.

The findings have critical implications for local, national, and international HIV and HCV testing strategies. The NSW DBS Pilot is ongoing but the possibilities for integration into standard of care are limited by the regulatory environment. HIV testing from DBS sampling is currently approved by the Therapeutic Goods Administration in Australia. However, there are no approved tests for HCV RNA testing outside of a research study, despite DBS being included in WHO recommendations for HCV testing [35], limiting potential integration of DBS into HCV clinical care. Approval would allow DBS to be used as a tool to facilitate HIV and HCV diagnosis outside of a research study and improve access to testing among priority populations and people not recently tested. Alternatively, collecting fingerstick capillary whole-blood samples using microvette sample collection devices for testing in central laboratories could be a viable option in the current regulatory context, and has been used in the UK [36] and Myanmar [37]. Any scale-up of DBS testing should consider support for more frequent high intensity testing campaigns carried out in in prison. The minimal training required to perform DBS makes it a valuable tool to expand the scope of practice in allied health workers including Aboriginal Health Workers and peer workers in harm reduction services. DBS testing via online self-registration is a strategy to improve testing uptake amongst priority populations living in regional and remote areas. Although point-of-care testing for HIV and HCV can allow fast delivery of results to facilitate single visit test-and-treat, there is still a need for a range of testing modalities. Point-of-care HCV RNA testing platforms are expensive and require considerable training due to the increased complexity for operation of point-of-care devices, which may limit scale-up across all services that may be performing testing. DBS allows sample collection with minimal resources (suitable for outreach and to allow people to collect their own sample) and allows sample collection in extreme weather conditions. The latter is important in the Australian context where hot weather can impact functioning of rapid point-of-care testing machines. Further, DBS testing can be combined with point-of-care antibody testing by using it as a reflex testing approach in people who are HCV antibody positive.

There are limitations to this study. Processes for recruitment and treatment initiation were not standardised across pathways and community sites. Some sites provided linkage to care on-site while others referred off-site. Changes to the survey throughout the study period impacted the quality of some variables including recent injecting and recent HCV testing. The lack of control arm is also a limitation. A wider range of approved sample types by the Therapeutic Goods Administration could improve the uptake of HIV and HCV testing but an important element of this is understanding the cost-effectiveness of each modality. An ongoing study will compare testing via DBS sample with other testing modalities to inform decision-making for the implementation of different testing strategies.

Strategies are needed to improve HIV and HCV testing, to improve treatment initiation, and reach national and international elimination targets. The evaluation of the first four years of the NSW DBS Pilot demonstrates that large-scale DBS sampling is feasible and could improve reach of testing, particularly in prisons and for people who do not frequently test. DBS provides a useful innovation to expand testing for HIV and HCV in Australia and facilitate the goal of ending the HIV and HCV epidemics.