Acceptability and feasibility of point-of-care CD4 testing on HIV continuum of care in low and middle income countries: a systematic review

Accurate and reproducible enumeration of CD4 T cell counts and Hemoglobin levels using a point of care system: Comparison with conventional laboratory based testing systems in a clinical reference laboratory in Cameroon

BACKGROUND

Measurements of CD4 T cells and hemoglobin (Hb) are conventionally used to determine the immunological state and disease progression for HIV-infected patients. We obtained a small lightweight point-of-care device, the BD FACSPrestoTM in order to demonstrate its ability to deliver CD4 and Hb analysis in comparison with two larger clinical machines the BDFACSCantoTM analyzer and Sysmex XN 1000 haematology analyzer. The advantages of using the POC device include access to HIV patient data in remote and in resource limited settings.

METHOD

The analytical performance of the BD FACSPrestoTM, compared with the FACSCantoTM II flow cytometer and the Sysmex XN 1000 haematology analyzer was evaluated by testing 241 routine clinical specimens collected in EDTA tubes from patients attending the Immunology and Microbiology laboratory of Chantal BIYA International Reference Centre (Yaounde, Cameroon) between January and May 2016.

RESULTS

The mean in absolute counts and percentage of CD4 T cells was 606 cells/mL and 25% respectively via the FACSPrestoTM, and 574 cells/mL and 24% respectively via the BD FACSCantoTM II. The mean concentration of Hb levels was 11.90 on the Sysmex XN 1000 and 11.45 via the BD FACSPrestoTM, A high correlation (R2 = 0.95, P < 0.001) of Hb level measurements was noted between the BD FACSPrestoTM and Sysmex XN 1000 hematology analyzer. Overall, a Bland-Altman plot of the differences between the two methods showed an excellent agreement for absolute and percentage CD4 counts and hemoglobin measurements between POC and conventional methods evaluated here. Furthermore, the study demonstrated the ease of use of the BD FACSPrestoTM POC technology in remote areas.

CONCLUSION

The BD FACPrestoTM is a suitable tool for CD4 enumeration in resource-limited settings, specifically providing a deployable, reliable POC testing option. The BD FACSPrestoTM performed appropriately in comparison to the conventional reference standard technologies. The BD FACSPrestoTM, system provides accurate, reliable, precise CD4/%CD4/Hb results on venous blood sampling. The data showed good agreement between the BD FACSPrestoTM, BD FACSCantoTM II and Sysmex XN 1000 XN 1000 systems.

Accuracy of point-of-care HIV and CD4 field testing by lay healthcare workers in the Botswana Combination Prevention Project

Accurate HIV and CD4 testing are critical in program implementation, with HIV misdiagnosis having serious consequences at both the client and/or community level. We implemented a comprehensive training and Quality Assurance (QA) program to ensure accuracy of point-of-care HIV and CD4 count testing by lay counsellors during the Botswana Combination Prevention Project (BCPP). We compared the performance of field testing by lay counsellors to results from an accredited laboratory to ascertain accuracy of testing. All trained lay counsellors passed competency assessments and performed satisfactorily in proficiency testing panel evaluations in 2013, 2014, and 2015. There was excellent agreement (99.6 %) between field and laboratory-based HIV test results; of the 3002 samples tested, 960 and 2030 were concordantly positive and negative respectively, with 12 misclassifications (kappa score 0.99, p < 0.0001). Of the 149 HIV-positive samples enumerated for CD4 count in the field using PIMA at a threshold of ≤ 350 cells/µl; there was 86 % agreement with laboratory testing, with only 21 misclassified. The mean difference between field and lab CD4 testing was - 16.16 cells/µl (95 % CI -5.4 to 26.9). Overall, there was excellent agreement between field and laboratory results for both HIV rapid test and PIMA CD4 results. A standard training package to train lay counsellors to accurately perform HIV and CD4 point-of-care testing in field settings was feasible, with point-of-care results obtained by lay counsellors comparable to laboratory-based testing.

Denys R, Lund C, Worthington C. Assessing the acceptability of dried blood spot testing for HIV and STBBI among Métis people in a community driven pilot project in Alberta, Canada

BACKGROUND

Little literature exists on culturally grounded approaches for addressing human immunodeficiency virus (HIV) and sexually transmitted and blood-borne infections (STBBI) among Métis people. The goal of this mixed-methods research was to explore the experiences of Métis community members participating in a dried blood spot testing (DBST) for HIV/STBBI pilot for Métis communities in Alberta, Canada, with the aim of assessing the acceptability of this testing method.

METHODS

Grounded in community-based and Indigenous research approaches and working in partnership with a Métis community-based organization, data collection included a survey and four gathering circles with Métis DBST recipients at one of two community events, and semi-structured interviews with three DBST providers.

RESULTS

Twenty-six of the 30 DBST recipients completed surveys, and 19 DBST recipients participated in gathering circles. Survey results suggest DBST is a highly acceptable STBBI testing method to Métis community members. Thematic analysis of gathering circle and interview transcripts revealed four broad themes related to the participants' experiences with DBST related to its acceptability (i. ease of DBST process, ii. overcoming logistical challenges associated with existing STBBI testing, iii. Reducing stigma through health role models and event-based, and iv. Métis-specific services).

CONCLUSIONS

These findings illustrate the potential for DBST to be part of a culturally grounded, Métis-specific response to HIV and STBBI.

Left behind on the path to 90-90-90: understanding and responding to HIV among displaced people

INTRODUCTION

In 2021, the number of people affected by displacement worldwide reached the highest on record, with an estimated 30.5 million refugees and 4.6 million asylum seekers seeking safety across international borders and further 53.2 million people displaced within their countries of origin. Most forcibly displaced persons come from or relocate to lower- and middle-income countries (LMICs) and many of those countries have large HIV epidemics. In this commentary, we describe some of the challenges at the intersection of HIV and displacement vulnerabilities that cannot be easily addressed in resource-limited environments.

DISCUSSION

HIV transmission and prevention and treatment efforts in the context of displacement are affected by myriad behavioural, social and structural factors across different stages of the displacement journey. For example, structural barriers faced by people experiencing displacement in relation to HIV prevention and care include funding constraints and legal framework deficiencies. Such barriers prevent all forced migrants, and particularly those whose sexual identities or practices are stigmatized against, access to prevention and care equal to local residents. Xenophobia, racism and other social factors, as well as individual risky behaviours facilitated by experiences of forced migration, also affect the progress towards 90-90-90 targets in displaced populations. Current evidence suggests increased HIV vulnerability in the period before displacement due to the effect of displacement drivers on medical supplies and infrastructure. During and after displacement, substantial barriers to HIV testing exist, though following resettlement in stable displacement context, HIV incidence and viral suppression are reported to be similar to those of local populations.

CONCLUSIONS

Experiences of often-marginalized displaced populations are diverse and depend on the context of displacement, countries of origin and resettlement, and the nature of the crises that forced these populations to move. To address current gaps in responses to HIV in displacement contexts, research in LMIC, particularly in less stable resettlement settings, needs to be scaled up. Furthermore, displaced populations need to be specifically addressed in national AIDS strategies and HIV surveillance systems. Finally, innovative technologies, such as point-of-care viral load and CD4 testing, need to be developed and introduced in settings facing displacement.

A profile of the Visitect® CD4 and Visitect® CD4 advanced disease for management of people living with HIV

INTRODUCTION

CD4 testing plays an important role in clinical management and epidemiological surveillance of HIV disease. Rapid, point-of-care (POC) CD4 tests can improve patients' access to CD4 testing, enabling decentralization of HIV services.

AREAS COVERED

We conducted a profile review of the Visitect®CD4 and the Visitect®CD4 Advanced Disease (Omega Diagnostics, UK) - the two lateral flow, equipment-free POC CD4 tests, which can be used to identify people with HIV who have CD4 of less than 350 and 200 cells/μl, respectively. Using published data from independent studies, we discussed the performance and utility of these tests, highlighting the advantages as well as their limitations.

EXPERT OPINION

The tests are user-friendly, acceptable to health care workers, and feasible to implement in primary health care settings and can provide reliable results for clinical decision-making. Hands-on training with pictorial instructions for use is needed to enhance test's operator confidence in interpretation of test results. Quality assurance program should be in place to ensure the quality of testing. Development of a next-generation test with a cutoff of 100 cells/μl is recommended to identify patients with advanced immunosuppression for initiation of prophylaxis to reduce HIV-related death. Operational research is also needed to identify cost-effective implementation strategies in real-world settings.

Implementability of healthcare interventions: an overview of reviews and development of a conceptual framework

Background

Implementation research may play an important role in reducing research waste by identifying strategies that support translation of evidence into practice. Implementation of healthcare interventions is influenced by multiple factors including the organisational context, implementation strategies and features of the intervention as perceived by people delivering and receiving the intervention. Recently, concepts relating to perceived features of interventions have been gaining traction in published literature, namely, acceptability, fidelity, feasibility, scalability and sustainability. These concepts may influence uptake of healthcare interventions, yet there seems to be little consensus about their nature and impact. The aim of this paper is to develop a testable conceptual framework of implementability of healthcare interventions that includes these five concepts.

Methods

A multifaceted approach was used to develop and refine a conceptual framework of implementability of healthcare interventions. An overview of reviews identified reviews published between January 2000 and March 2021 that focused on at least one of the five concepts in relation to a healthcare intervention. These findings informed the development of a preliminary framework of implementability of healthcare interventions which was presented to a panel of experts. A nominal group process was used to critique, refine and agree on a final framework.

Results

A total of 252 publications were included in the overview of reviews. Of these, 32% were found to be feasible, 4% reported sustainable changes in practice and 9% were scaled up to other populations and/or settings. The expert panel proposed that scalability and sustainability of a healthcare intervention are dependent on its acceptability, fidelity and feasibility. Furthermore, acceptability, fidelity and feasibility require re-evaluation over time and as the intervention is developed and then implemented in different settings or with different populations. The final agreed framework of implementability provides the basis for a chronological, iterative approach to planning for wide-scale, long-term implementation of healthcare interventions.

Conclusions

We recommend that researchers consider the factors acceptability, fidelity and feasibility (proposed to influence sustainability and scalability) during the preliminary phases of intervention development, evaluation and implementation, and iteratively check these factors in different settings and over time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13012-021-01171-7.

Lay testing cadres and point-of-care diagnostic tests for HIV and other diseases: An essential combination in health service delivery

Zibusiso Ndlovu and Tom Ellman discuss the potential value of task sharing in provision of testing for HIV and other infectious diseases.

Performance characteristics of an instrument-free point-of-care CD4 test (VISITECT®CD4) for use in resource-limited settings

Objective

CD4+ T lymphocyte count remains the most common biomarker of immune status and disease progression in human immunodeficiency virus (HIV)-positive individuals. VISITECT®CD4 is an instrument-free, low-cost point-of-care CD4 test with a cut-off of 350 CD4 cells/μL. This study aimed to evaluate VISITECT®CD4 test's diagnostic accuracy.

Methods

Two hundred HIV-positive patients attending a tertiary HIV centre in South India were recruited. Patients provided venous blood for reference and VISITECT®CD4 tests. An additional finger-prick blood sample was obtained for VISITECT®CD4. VISITECT®CD4's diagnostic performance in identifying individuals with CD4 counts ≤350 cells/μL was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) taking flow cytometry as the reference.

Results

The overall agreement between VISITECT®CD4 and flow cytometry was 89.5% using venous blood and 81.5% using finger-prick blood. VISITECT®CD4 showed better performance using venous blood [sensitivity: 96.6% (95% confidence interval: 92.1%–98.9%), specificity: 70.9% (57.1%–82.4%), PPV: 89.7% (83.9%–94.0%) and NPV: 88.6% (75.4%–96.2%)] than using finger-prick blood [sensitivity: 84.8% (77.9%–90.2%), specificity: 72.7% (59.0%–83.9%), PPV: 89.1% (82.7%–93.8%) and NPV: 64.5% (51.3%–76.3%)].

Conclusion

VISITECT®CD4 performed well using venous blood, demonstrating its potential utility in decentralization of CD4 testing services in resource-constrained settings.

Feasibility and acceptability of implementing early infant diagnosis of HIV in Papua New Guinea at the point of care: a qualitative exploration of health worker and key informant perspectives

INTRODUCTION

Early infant diagnosis (EID) of HIV and timely initiation of antiretroviral therapy can significantly reduce morbidity and mortality among HIV-positive infants. Access to EID is limited in many low-income and middle-income settings, particularly those in which standard care involves dried blood spots (DBS) sent to centralised laboratories, such as in Papua New Guinea (PNG). We conducted a qualitative exploration of the feasibility and acceptability of implementing a point-of-care (POC) EID test (Xpert HIV-1 Qualitative assay) among health workers and key stakeholders working within the prevention of mother-to-child transmission of HIV (PMTCT) programme in PNG.

METHODS

This qualitative substudy was conducted as part of a pragmatic trial to investigate the effectiveness of the Xpert HIV-1 Qualitative test for EID in PNG and Myanmar. Semistructured interviews were undertaken with 5 health workers and 13 key informants to explore current services, experiences of EID testing, perspectives on the Xpert test and the feasibility of integrating and scaling up POC EID in PNG. Coding was undertaken using inductive and deductive approaches, drawing on existing acceptability and feasibility frameworks.

RESULTS

Health workers and key informants (N=18) felt EID at POC was feasible to implement and beneficial to HIV-exposed infants and their families, staff and the PMTCT programme more broadly. All study participants highlighted starting HIV-positive infants on treatment immediately as the main advantage of POC EID compared with standard care DBS testing. Health workers identified insufficient resources to follow up infants and caregivers and space constraints in hospitals as barriers to implementation. Participants emphasised the importance of adequate human resources, ongoing training and support, appropriate coordination and a sustainable supply of consumables to ensure effective scale-up of the test throughout PNG.

CONCLUSIONS

Implementation of POC EID in a low HIV prevalence setting such as PNG is likely to be both feasible and beneficial with careful planning and adequate resources.

TRIAL REGISTRATION NUMBER

12616000734460.

Point of Care Diagnostics in Resource-Limited Settings: A Review of the Present and Future of PoC in Its Most Needed Environment

Point of care (PoC) diagnostics are at the focus of government initiatives, NGOs and fundamental research alike. In high-income countries, the hope is to streamline the diagnostic procedure, minimize costs and make healthcare processes more efficient and faster, which, in some cases, can be more a matter of convenience than necessity. However, in resource-limited settings such as low-income countries, PoC-diagnostics might be the only viable route, when the next laboratory is hours away. Therefore, it is especially important to focus research into novel diagnostics for these countries in order to alleviate suffering due to infectious disease. In this review, the current research describing the use of PoC diagnostics in resource-limited settings and the potential bottlenecks along the value chain that prevent their widespread application is summarized. To this end, we will look at literature that investigates different parts of the value chain, such as fundamental research and market economics, as well as actual use at healthcare providers. We aim to create an integrated picture of potential PoC barriers, from the first start of research at universities to patient treatment in the field. Results from the literature will be discussed with the aim to bring all important steps and aspects together in order to illustrate how effectively PoC is being used in low-income countries. In addition, we discuss what is needed to improve the situation further, in order to use this technology to its fullest advantage and avoid “leaks in the pipeline”, when a promising device fails to take the next step of the valorization pathway and is abandoned.

Influence of evolving HIV treatment guidance on CD4 counts and viral load monitoring: A mixed-methods study in three African countries

Little is known about how CD4 and viral load testing have evolved following implementation of universal test and treat (UTT) in African settings. We reviewed World Health Organization (WHO) guidance from 2013 to 2018, and compared it against national HIV policies in Malawi, Tanzania and South Africa. Three surveys rounds were conducted in 2013, 2016 and 2017–2018 in 33 health facilities across the three settings to assess implementation of national policies on the use of biological markers. Qualitative interviews were conducted with 26 HIV policymakers or programme managers, 21 providers and 66 people living with HIV to explore understandings and experiences of these tests. Various factors influenced adoption and implementation of WHO guidance, including historical policies on CD4 counts, governance issues, supply chain challenges and funding mechanisms. Facility-level practices relating to the use of these tests often diverged from national policies. Patients and providers valued both tests, but did not always understand their roles. In addition to continued support for scaling-up viral load testing, renewed focus should be placed on the ongoing value of point-of-care CD4 tests in the UTT era, including its role in assessing disease progression and informing clinical management of cases to reduce HIV-related mortality.

Diagnostic performance and usability of the VISITECT CD4 semi-quantitative test for advanced HIV disease screening

BACKGROUND

In sub-Saharan Africa, a third of people starting antiretroviral therapy and majority of patients returning to HIV-care after disengagement, present with advanced HIV disease (ADH), and are at high risk of mortality. Simplified and more affordable point-of-care (POC) diagnostics are required to increase access to prompt CD4 cell count screening for ambulatory and asymptomatic patients. The Visitect CD4 Lateral Flow Assay (LFA) is a disposable POC test, providing a visually interpreted result of above or below 200 CD4cells/mm3. This study evaluated the diagnostic performance of this index test.

METHODS

Consenting patients above 18years of age and eligible for CD4 testing were enrolled in Nsanje district hospital (Malawi), Gutu mission hospital (Zimbabwe) and Centre hopitalier de Kabinda (DRC). A total of 708 venous blood samples were tested in the index test and in the BD FACSCount assay (reference test method) in the laboratories (Phase 1) to determine diagnostic accuracy. A total of 433 finger-prick (FP) samples were tested on the index test at POC by clinicians (Phase 2) and a self-completed questionnaire was administered to all testers to explore usability of the index test.

RESULTS

Among 708 patients, 67.2% were female and median CD4 was 297cells/mm3. The sensitivity of the Visitect CD4 LFA using venous blood in the laboratory was 95.0% [95% CI: 91.3-97.5] and specificity was 81.9% [95% CI: 78.2-85.2%]. Using FP samples, the sensitivity of the Visitect CD4 LFA was 98.3% [95% CI: 95.0-99.6] and specificity was 77.2% [95% CI: 71.6-82.2%]. Usability of the Visitect CD4 LFA was high across the study sites with 97% successfully completed tests. Due to the required specific multiple incubation and procedural steps during the Visitect CD4 LFA testing, few health workers (7/26) were not confident to manage testing whilst multi-tasking in their clinical work.

CONCLUSIONS

Visitect CD4 LFA is a promising test for decentralized CD4 screening in resource-limited settings, without access to CD4 testing and and it can trigger prompt management of patients with AHD. Lay health cadres should be considered to conduct Visitect CD4 LFA testing in PHCs as well as coordinating all other POC quality assurance.

Acceptability and feasibility of testing for HIV infection at birth and linkage to care in rural and urban Zambia: a cross-sectional study

BACKGROUND

Early infant diagnosis is important for timely identification of HIV-infected infants and linkage to care. Testing at birth has been implemented to facilitate earlier diagnosis of HIV infection but may present new challenges. This study was conducted to understand the acceptability and feasibility of birth testing in urban and rural settings in southern Zambia.

METHODS

This cross-sectional study was conducted at 11 hospitals and clinics in Livingstone, Choma, and Macha in Southern Province, Zambia from 2016 to 2018. Infants born to pregnant women living with HIV at the sites were eligible for enrollment. After enrollment, a questionnaire was administered to the mother and a dried blood spot card was collected from infants for testing at a central laboratory. When results were available, mothers were notified to return to the clinic. Acceptability of birth testing was evaluated based on the proportion of women who agreed to participate and the reasons for non-participation among women who declined. Feasibility of testing at birth was evaluated using turnaround times for returning results, the proportion of women receiving results, and linkage to care for infants testing positive.

RESULTS

One thousand four hundred three women were approached for the study. A small proportion declined due to refusal of birth testing (0 to 8.2% across sites). One thousand two hundred ninety women agreed to have their infants tested. The proportion of mothers receiving results ranged from 51.6 to 92.1%, and was significantly lower at the hospital than clinics in Livingstone (51.6% vs. 69.8%; p < 0.0001) and Macha (69.5% vs. 85.7%; p < 0.0001) but not Choma (85.7% vs. 92.1%; p = 0.34). For mothers who received test results, the median turnaround time from sample collection was 67 days in Livingstone and 53 days in Macha and Choma. Overall, 23 (1.8%) infants tested positive for HIV but only 8 (34.8%) were linked to care a median of 68 days (range: 29, 784) after sample collection.

CONCLUSIONS

While testing at birth was acceptable, this study highlights the operational challenges under a centralized laboratory testing system. Point-of-care platforms are needed for rapid testing and return of results so HIV-infected children can be identified, linked to care, and treated as early as possible.

Performance of non-laboratory staff for diagnostic testing and specimen collection in HIV programs: A systematic review and meta-analysis

BACKGROUND

In most high HIV burden countries, many HIV patients do not have reliable access to required diagnostic laboratory tests. Task shifting of clinical tasks to lower cadres of health care workers and lay counselors has been successful in scaling up treatment for HIV and may also be an effective strategy in expanding access to essential diagnostic testing.

METHODS

We screened major electronic databases between 1 January 2005 to 26 August 2018 to identify studies assessing ease of use and accuracy of task shifting of HIV-related diagnostic testing and/or specimen collection to non-laboratory health staff. Two independent reviewers screened all titles and abstracts for studies that analyzed diagnostic accuracy, patient impact, ease-of-use, or cost-effectiveness. Studies were assessed for quality, bias, and applicability following the QUADAS-2 framework. We generated summary estimates using random-effects meta-analyses.

RESULTS

We identified 42 relevant studies. Overall, point-of-care CD4 testing performed by non-laboratory staff had a mean bias of -54.44 (95% CI: -72.40 --36.48) compared to conventional laboratory-based. Though studies were limited, the diagnostic accuracy of point-of-care alanine transaminase enzyme (ALT) and hemoglobin testing performed by non-laboratory staff was comparable to conventional laboratory-based testing by laboratory professionals. Point-of-care testing and/or specimen collection were generally found to be acceptable and easy to use for non-laboratory staff.

CONCLUSIONS

Task shifting of testing using point-of-care technologies to non-laboratory staff was comparable to laboratory professionals operating the same technology in the laboratory. Some variability was observed comparing the performance of point-of-care CD4 testing by non-laboratory staff to conventional laboratory-based technologies by laboratory professionals indicating potential lower performance was likely technological rather than operator caused. The benefits of task shifting of testing may outweigh any possible harms as task shifting allows for increased decentralization, access of specific diagnostics, and faster result delivery.

Toward Improving Accessibility of Point-of-Care Diagnostic Services for Maternal and Child Health in Low- and Middle-Income Countries

Point-of-care (POC) testing can improve health care provision in settings with limited access to health care services. Access to POC diagnostic services has shown potential to alleviate some diagnostic challenges and delays associated with laboratory-based methods in low- and middle-income countries. Improving accessibility to POC testing (POCT) services during antenatal and perinatal care is among the global health priorities to improve maternal and child health. This review provides insights on the availability of POC testing designed for diagnosing HIV, syphilis, and malaria in pregnancy to improve maternal and child health. In addition, factors such as accessibility of POC testing, training of health work force, and the efficiency of POC testing services delivery in low- and middle-income countries are discussed. A framework to help increase access to POC diagnostic services and improve maternal and child health outcomes in low- and middle-income countries is proposed.

Performance of the BD-FACS Presto for CD4 count and hemoglobin measurement in a district hospital and rural laboratory in Ghana

Introduction

In Ghana, initiation of Antiretroviral Therapy (ART) is recommended for all patients with an HIV diagnosis, regardless of CD4+ T-cell count. However, measurement of CD4 count remains an important metric for identifying patients with advanced HIV disease, and assessing a person’s overall immune status, which informs the decision to offer opportunistic infection screening and prophylaxis. Access to CD4+ T cell count in rural health facilities remains a major challenge in Ghana and other resource-limited settings. This study aimed to validate the accuracy of the BD FACSPresto near-patient device for measurement of CD4 count and hemoglobin concentration against the FACSCount (CD4) and Sysmex (hemoglobin) diagnostic machines when operated in both a district hospital and rural laboratory, serving a network of health posts in Ashanti Region, Ghana.

Methodology

In the first phase of the study, patients were recruited from a district hospital, and both venous and capillary blood samples were tested using the FACSCount and Sysmex as reference tests and compared to results of the FACSPresto performed in the clinic laboratory at the district hospital. In the second phase, patients were recruited from both the hospital and from rural health clinics, and samples were tested using the FACSPresto at a rural laboratory. Sensitivity and specificity among samples categorized into different clinically relevant CD4 count ranges were calculated, along with correlation between the Presto and the reference measurements, and mean and relative bias with limits of agreement.

Results

The FACSPresto was successfully operated in both clinical settings. A total of 59 samples in the first phase and 48 samples in the second phase were included. Positive bias was observed when comparing CD4 count measured by BD FACSPresto to FACSCount in the district hospital (bias = 44, LOA -72,160) and in the rural laboratory setting (bias = 74, LOA -96, 244). In addition, capillary blood samples were shown to give higher measures when compared to venous blood samples from the same participant. All results were statistically significant (p<0.05) apart from hemoglobin measurement in venous blood in the rural laboratory. Correlation coefficients were high for CD4 count measures and lower for hemoglobin measures.

Conclusion

Overall, the Presto gave higher estimates of CD4 count compared to FACSCount, and hemoglobin measurements were higher than from Sysmex. Samples of capillary blood in turn gave higher results for both measurements compared to venous blood, consistent with previous analyses. These findings should be considered when selecting CD4 count machines for use at the point of care, especially in remote areas where capillary blood sampling may be preferable, but are likely balanced by device’s ease of use, portability, and ability to expand access to services. These results are some of the first to demonstrate the accuracy of the FACSPresto in West Africa and show that this device can be successfully operated in a very rural lab setting and may therefore assist to provide CD4 count and hemoglobin concentration measurement to populations in need.

Qualitative assessment of South African healthcare worker perspectives on an instrument-free rapid CD4 test

Background

Accurate measurement of CD4 cell counts remains an important tenet of clinical care for people living with HIV. We assessed an instrument-free point-of-care CD4 test (VISITECT® CD4) based on a lateral flow principle, which gives visual results after 40 min. The test involves five steps and categorises CD4 counts as above or below 350 cells/μL. As one component of a performance evaluation of the test, this qualitative study explored the views of healthcare workers in a large women and children’s hospital on the acceptability and feasibility of the test.

Methods

Perspectives on the VISITECT® CD4 test were elicited through in-depth interviews with eight healthcare workers involved in the performance evaluation at an antenatal care facility in Johannesburg, South Africa. Audio recordings were transcribed in full and analysed thematically.

Results

Healthcare providers recognised the on-going relevance of CD4 testing. All eight perceived the VISITECT® CD4 test to be predominantly user-friendly, although some felt that the need for precision and optimal concentration in performing test procedures made it more challenging to use. The greatest strength of the test was perceived to be its quick turn-around of results. There were mixed views on the semi-quantitative nature of the test results and how best to integrate this test into existing health services. Participants believed that patients in this setting would likely accept the test, given their general familiarity with other point-of-care tests.

Conclusions

Overall, the VISITECT® CD4 test was acceptable to healthcare workers and those interviewed were supportive of scale-up and implementation in other antenatal care settings. Both health workers and patients will need to be oriented to the semi-quantitative nature of the test and how to interpret the results of tests.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-3948-x) contains supplementary material, which is available to authorized users.

Field Performance and Diagnostic Accuracy of a Low-Cost Instrument-Free Point-of-Care CD4 Test (Visitect CD4) Performed by Different Health Worker Cadres among Pregnant Women

Measuring CD4 counts remains an important component of HIV care. The Visitect CD4 is the first instrument-free low-cost point-of-care CD4 test with results interpreted visually after 40 min, providing a result of ≥350 CD4 cells/mm3 The field performance and diagnostic accuracy of the test was assessed among HIV-infected pregnant women in South Africa. A nurse performed testing at the point-of-care using both venous and finger-prick blood, and a counselor and laboratory staff tested venous blood in the clinic laboratory (four Visitect CD4 tests/participant). Performance was compared to the mean CD4 count from duplicate flow cytometry tests on venous blood (FACSCalibur Trucount). In 2017, 156 patients were enrolled, providing a total of 624 Visitect CD4 tests (468 venous and 156 finger-prick samples). Of 624 tests, 28 (4.5%) were inconclusive. Generalized linear mixed modeling showed better performance of the test on venous blood (sensitivity = 81.7%; 95% confidence interval [CI] = 72.3 to 91.1]; specificity = 82.6%, 95% CI = 77.1 to 88.1) than on finger-prick specimens (sensitivity = 60.7%; 95% CI = 45.0 to 76.3; specificity = 89.5%, 95% CI = 83.2 to 95.8; P = 0.001). No difference in performance was detected by cadre of health worker (P = 0.113) or between point-of-care versus laboratory-based testing (P = 0.108). Adequate performance of Visitect CD4 with different operators and at the point of care, with no need of electricity or instrument, shows the potential utility of this device, especially for facilitating decentralization of CD4 testing services in rural areas.

Forecasting the global demand for HIV monitoring and diagnostic tests: A 2016-2021 analysis

Introduction

Despite considerable progress, just over half of the 37 million people eligible to start antiretroviral therapy (ART) have accessed treatment and millions of HIV-positive people still do not know their status. With demand for ART continuing to grow, meeting the ambitious 90-90-90 HIV treatment targets will depend on improved access to high-quality diagnostics to both diagnose infection and monitor treatment adherence in low and middle-income countries (LMICs). Robust projections of future demand for CD4, viral load (VL), HIV early-infant-diagnosis (EID) tests and HIV rapid diagnostic tests (RDTs) are needed as scale-up continues.

Methods

We estimate the current coverage for HIV diagnostics and project future demand to 2021 using a consolidated forecast using data on past coverage and current demand from a number of sources, from 130 predominantly LMIC countries.

Results

We forecast that the overall number of CD4 tests is expected to decline between now and 2021 as more countries adopt test-and-treat and shift to VL testing for patient monitoring. Our consolidated forecast projects a gradual decline in demand for CD4 tests to 16.6 million by 2021. We anticipate that demand for VL tests will increase to 28.5 million by 2021, reflecting the increasing number of people who will receive ART and the adoption of VL testing for patient monitoring. We expect that the demand for EID tests will grow more rapidly than in past years, driven by the implementation of testing at birth in programmes globally, in line with WHO guideline recommendations, doubling to 2.1 million tests by 2021. Demand for rapid diagnostic tests is also likely to increase, reaching 509 million tests by 2021.

Discussion

In order to achieve the ambitious 90-90-90 targets, it will be essential to maintain and improve access to CD4, VL, EID tests and RDTs. These projections provide insight into the global demand we can expect to see for these HIV monitoring and diagnostic tests, both in relation to historical trends, and the 90-90-90 targets. Our projections will better enable producers to ensure adequate supply, and to support procurement organisations in planning future funding and purchase plans to meet the anticipated demand. The findings highlight the ongoing need for governments and international funding bodies to prioritise improving capacity and access to HIV diagnostic and monitoring technologies in line with demand.

Piloting very early infant diagnosis of HIV in Lesotho: Acceptability and feasibility among mothers, health workers and laboratory personnel

Introduction

Mortality associated with in-utero HIV infection rises rapidly within weeks after birth. Very early infant diagnosis of HIV (VEID)–testing within 2 weeks of birth–followed by immediate initiation of antiretroviral therapy has potential to avert mortality associated with in-utero transmission. However, our understanding of acceptability and feasibility of VEID is limited.

Methods

VEID was piloted in an observational prospective cohort of HIV-positive pregnant women and their infants in 13 Lesotho health facilities. Between March-July 2016, semi-structured interviews were conducted with HIV-positive women attending 6-week or 14-week postnatal visits and health workers (HWs) in 8 study facilities in 3 districts as well as with district and central laboratory staff. Interview themes included acceptability of birth and subsequent HIV testing and early treatment, perceived VEID challenges, and HIV birth testing procedures and how well they were performed.

Results

Interviews were conducted with 20 women, 18 HWs and 9 district/central laboratory staff. Nearly all mothers perceived knowing their child’s HIV status at birth positively. Mothers and HWs did not indicate that birth testing affected subsequent acceptance of infant HIV testing or clinic attendance. HWs and laboratory staff reported weak follow-up systems for mothers with home deliveries, and concern regarding the increased workload associated with additional testing requirements. All groups reported turnaround time delays for EID, and that sometimes results were never received.

Conclusions

Women, HWs, and laboratory staff found VEID acceptable and were supportive of national implementation of birth testing. However, they identified challenges within the EID system that could be exacerbated by adding a test to the diagnostic algorithm, such as delays in receiving test results, suggesting VEID may not be feasible in certain settings. Policymakers will need to consider whether adding birth testing or strengthening the current clinic and laboratory system is the most appropriate course of action.

Forecasting the global demand for HIV monitoring and diagnostic tests: A 2016-2021 analysis

INTRODUCTION

Despite considerable progress, just over half of the 37 million people eligible to start antiretroviral therapy (ART) have accessed treatment and millions of HIV-positive people still do not know their status. With demand for ART continuing to grow, meeting the ambitious 90-90-90 HIV treatment targets will depend on improved access to high-quality diagnostics to both diagnose infection and monitor treatment adherence in low and middle-income countries (LMICs). Robust projections of future demand for CD4, viral load (VL), HIV early-infant-diagnosis (EID) tests and HIV rapid diagnostic tests (RDTs) are needed as scale-up continues.

METHODS

We estimate the current coverage for HIV diagnostics and project future demand to 2021 using a consolidated forecast using data on past coverage and current demand from a number of sources, from 130 predominantly LMIC countries.

RESULTS

We forecast that the overall number of CD4 tests is expected to decline between now and 2021 as more countries adopt test-and-treat and shift to VL testing for patient monitoring. Our consolidated forecast projects a gradual decline in demand for CD4 tests to 16.6 million by 2021. We anticipate that demand for VL tests will increase to 28.5 million by 2021, reflecting the increasing number of people who will receive ART and the adoption of VL testing for patient monitoring. We expect that the demand for EID tests will grow more rapidly than in past years, driven by the implementation of testing at birth in programmes globally, in line with WHO guideline recommendations, doubling to 2.1 million tests by 2021. Demand for rapid diagnostic tests is also likely to increase, reaching 509 million tests by 2021.

DISCUSSION

In order to achieve the ambitious 90-90-90 targets, it will be essential to maintain and improve access to CD4, VL, EID tests and RDTs. These projections provide insight into the global demand we can expect to see for these HIV monitoring and diagnostic tests, both in relation to historical trends, and the 90-90-90 targets. Our projections will better enable producers to ensure adequate supply, and to support procurement organisations in planning future funding and purchase plans to meet the anticipated demand. The findings highlight the ongoing need for governments and international funding bodies to prioritise improving capacity and access to HIV diagnostic and monitoring technologies in line with demand.

Assessing Very Early Infant Diagnosis Turnaround Times: Findings from a Birth Testing Pilot in Lesotho

Very early infant diagnosis (VEID) (testing within two weeks of life), combined with rapid treatment initiation, could reduce early infant mortality. Our study evaluated turnaround time (TAT) to receipt of infants' HIV test results and ART initiation if HIV-infected, with and without birth testing availability. Data from facility records and national databases were collected for 12 facilities offering VEID, as part of an observational prospective cohort study, and 10 noncohort facilities. HIV-exposed infants born in January-June 2016 and any cohort infant diagnosed as HIV-infected at birth or six weeks were included. The median TAT from blood draw to caregiver result receipt was 76.5 days at birth and 63 and 70 days at six weeks at cohort and noncohort facilities, respectively. HIV-exposed infants tested at birth were approximately one month younger when their caregivers received results versus those tested at six weeks. Infants diagnosed at birth initiated ART about two months earlier (median 6.4 weeks old) than those identified at six weeks (median 14.8 weeks). However, the long TAT for testing at both birth and six weeks illustrates the prolonged process for specimen transport and result return that could compromise the effectiveness of adding VEID to existing overburdened EID systems.

Point-of-care diagnostics: extending the laboratory network to reach the last mile

Purpose of review

More point-of-care (POC) diagnostic tests are becoming available for HIV diagnosis and treatment in resource-limited settings. These novel technologies have the potential to foster decentralized HIV care and treatment for the benefit of clinical laboratories, HIV clinics, and HIV-infected patients. There continue to be many business, technological, and operational challenges that limit product development and regulatory approval, which limits products available for the required operational and cost-effectiveness studies and delays policy adoption and implementation.

Recent findings

Although the rapid HIV diagnostic test has been widely successful, the pathways for POC CD4⁺ cell count and HIV viral load assay analyzers have been more challenging. We describe significant hurdles for product development, approval, and implementation, which include the business case, technical development, clinical impact, and integrating laboratory and clinical networks.

Summary

The objective of this review is to highlight the obstacles for developing and implementing appropriate strategies for POC HIV testing assays to improve the clinical services for HIV-infected patients in resource-limited settings.

Impact of Point-of-Care CD4 Testing on Retention in Care Among HIV-Positive Pregnant and Breastfeeding Women in the Context of Option B+ in Zimbabwe: A Cluster Randomized Controlled Trial

INTRODUCTION

Scale-up of Option B+ in Zimbabwe has increased antiretroviral therapy (ART) coverage but patient loss-to-follow-up remains high; thus, effective strategies to improve retention in care are needed. Evidence for Elimination, a cluster randomized controlled trial, evaluated the impact of point-of-care (POC) CD4 testing with CD4 count-specific adherence counseling on rates of retention among 1150 HIV-positive pregnant women initiating ART in Zimbabwe.

METHODS

Thirty-two primary care health facilities were randomized to offer either standard-of-care (SOC) or POC CD4 testing plus CD4-specific counseling to clients (POC Plus). The primary outcome was the proportion of HIV-positive pregnant women retained on ART after 12 months, calculated by cluster-adjusted proportions, unadjusted and adjusted relative risks (RR and aRR, respectively).

RESULTS

Retention in care 12 months after initiation was 50.7% and 54.5% in the POC Plus and SOC arms, respectively (RR 0.93, 95% confidence interval [CI]: 0.78 to 1.11; aRR 0.91, 95% CI: 0.77 to 1.07). Although considered not retained, 9.7% transferred to another facility and 0.2% died. Most women, 95.3% in POC Plus and 92.9% in SOC, initiated ART within 1 month of antenatal booking (RR 1.03, 95% CI: 0.97 to 1.08).

DISCUSSION

Although patient retention was similar in both arms, women in the POC Plus arm were more likely to have received a CD4 test at booking and a repeat CD4 test later in care. CD4 is no longer required for treatment initiation but is still recommended in national guidelines and is of value in clinical management. Further work is needed to identify effective strategies to increase patient retention in ART care.