Diagnostic testing holds the key to NTD elimination.

"Fit-for-purpose" diagnostic tests have emerged as a prerequisite to achieving global targets for the prevention, control, elimination, and eradication of neglected tropical diseases (NTDs), as highlighted by the World Health Organization's (WHO) new roadmap. There is an urgent need for the development of new tools for those diseases for which no diagnostics currently exist and for improvement of existing diagnostics for the remaining diseases. Yet, efforts to achieve this, and other crosscutting ambitions, are fragmented, and the burden of these 20 debilitating diseases immense. Compounded by the Coronavirus Disease 2019 (COVID-19) pandemic, programmatic interruptions, systemic weaknesses, limited investment, and poor commercial viability undermine global efforts-with a lack of coordination between partners, leading to the duplication and potential waste of scant resources. Recognizing the pivotal role of diagnostic testing and the ambition of WHO, to move forward, we must create an ecosystem that prioritizes country-level action, collaboration, creativity, and commitment to new levels of visibility. Only then can we start to accelerate progress and make new gains that move the world closer to the end of NTDs.

A prospective multicentre diagnostic accuracy study for the Truenat tuberculosis assays.

BACKGROUND: Bringing reliable and accurate tuberculosis (TB) diagnosis closer to patients is a key priority for global TB control. Molbio Diagnostics have developed the Truenat point-of-care molecular assays for detection of TB and rifampicin (RIF) resistance. METHODS: We conducted a prospective multicentre diagnostic accuracy study at 19 primary healthcare centres and seven reference laboratories in Peru, India, Ethiopia and Papua New Guinea to estimate the diagnostic accuracy of the point-of-care Truenat MTB, MTB Plus and MTB-RIF Dx assays for pulmonary TB using culture and phenotypic drug susceptibility testing as the reference standard, compared with Xpert MTB/RIF or Ultra. RESULTS: Of 1807 enrolled participants with TB signs/symptoms, 24% were culture-positive for Mycobacterium tuberculosis, of which 15% were RIF-resistant. In microscopy centres, the pooled sensitivity of Truenat MTB and Truenat MTB Plus was 73% (95% CI 67-78%) and 80% (95% CI 75-84%), respectively. Among smear-negative specimens, sensitivities were 36% (95% CI 27-47%) and 47% (95% CI 37-58%), respectively. Sensitivity of Truenat MTB-RIF was 84% (95% CI 62-95%). Truenat assays showed high specificity. Head-to-head comparison in the central reference laboratories suggested that the Truenat assays have similar performance to Xpert MTB/RIF. CONCLUSION: We found the performance of Molbio's Truenat MTB, MTB Plus and MTB-RIF Dx assays to be comparable to that of the Xpert MTB/RIF assay. Performing the Truenat tests in primary healthcare centres with very limited infrastructure was feasible. These data supported the development of a World Health Organization policy recommendation of the Molbio assays.

Diagnostic Infectious Diseases Testing Outside Clinics: A Global Systematic Review and Meta-analysis.

BACKGROUND: Most people around the world do not have access to facility-based diagnostic testing, and the gap in availability of diagnostic tests is a major public health challenge. Self-testing, self-sampling, and institutional testing outside conventional clinical settings are transforming infectious disease diagnostic testing in a wide range of low- and middle-income countries (LMICs). We examined the delivery models of infectious disease diagnostic testing outside clinics to assess the impact on test uptake and linkage to care. METHODS: We conducted a systematic review and meta-analysis, searching 6 databases and including original research manuscripts comparing testing outside clinics with conventional testing. The main outcomes were test uptake and linkage to care, delivery models, and adverse outcomes. Data from studies with similar interventions and outcomes within thematic areas of interest were pooled, and the quality of evidence was assessed using GRADE. This study was registered in PROSPERO (CRD42019140828).We identified 10 386 de-duplicated citations, and 76 studies were included. Data from 18 studies were pooled in meta-analyses. Studies focused on HIV (48 studies), chlamydia (8 studies), and multiple diseases (20 studies). HIV self-testing increased test uptake compared with facility-based testing (9 studies: pooled odds ratio [OR], 2.59; 95% CI, 1.06-6.29; moderate quality). Self-sampling for sexually transmitted infections increased test uptake compared with facility-based testing (7 studies: pooled OR, 1.74; 95% CI, 0.97-3.12; moderate quality). Conclusions. Testing outside of clinics increased test uptake without significant adverse outcomes. These testing approaches provide an opportunity to expand access and empower patients. Further implementation research, scale-up of effective service delivery models, and policies in LMIC settings are needed.

Upfront Xpert MTB/RIF for diagnosis of pediatric TB-Does it work? Experience from India.

BACKGROUND: Diagnosis of TB in pediatric population poses several challenges. A novel initiative was implemented in several major cities of India aimed at providing upfront access to free-of-cost Xpert MTB/RIF to presumptive pediatric TB cases. This paper aims to describe the experience of implementing this large initiative and assess feasibility of the intervention in high TB burden settings. METHODS: Data were drawn from the pediatric TB project implemented in 10 major cities of India between April 2014 and March 2018. In each city, providers, both public and private, were engaged and linked with a high throughput Xpert MTB/RIF lab (established in that city) through rapid specimen transportation and electronic reporting system. Rates and proportions were estimated to describe the characteristics of this cohort. RESULTS: Of the total 94,415 presumptive pediatric TB cases tested in the project, 6,270 were diagnosed positive for MTB (6.6%) on Xpert MTB/RIF (vs 2% on smear microscopy). Among MTB positives, 545 cases were rifampicin resistant (8.7%). The median duration between collection of specimens and reporting of results was 0 days (same day) and >89% cases were initiated on treatment. Approximately 50% of the specimens tested were non-sputum. The number of providers/facilities engaged under the project increased >10-fold (from 124 in Q2'14 to 1416 in Q1'18). CONCLUSION: This project, which was one of the largest initiatives globally among pediatric population, demonstrated the feasibility of sustaining rapid and upfront access to free-of-cost Xpert MTB/RIF testing. The project underscores the efficiency of this rapid diagnostic assay in tackling several challenges in pediatric TB diagnosis, identifies opportunities for further interventions as well as brings to light scope for effective engagement with healthcare providers. The findings have facilitated a policy decision by National TB Programme mandating the use of Xpert MTB/RIF as a primary diagnostic tool for TB diagnosis in children, which is being scaled-up.

Application of a simple point-of-care test to reduce UK healthcare costs and adverse events in outpatient acute respiratory infections.

Background: Acute respiratory infection (ARI) accounts for over two-thirds of total antibiotic prescriptions although most are caused by viruses that do not benefit from antibiotics. Most antibiotics are prescribed in the outpatients setting. Antibiotic overuse leads to antibiotic-related adverse events (AEs), inclusive of secondary infections, resistance, and increased costs. Point-of-care tests (POCT) may reduce unnecessary antibiotics. A cost analysis was performed to assess diagnostic POCT options to identify patients with an ARI that may benefit from antibiotics in a United Kingdom (UK) outpatient setting.Methods: Healthcare savings were estimated using a budget impact analysis based on UK National Institute for Health and Care Excellence (NICE) data and direct costs (antibiotics, AEs, POCTs) derived from published literature. Otitis media, sinusitis, pharyngitis and bronchitis were considered the most common ARIs. Antibiotic-related AE costs were calculated using re-consultation costs for anaphylaxis, Stevens-Johnson syndrome, allergies/diarrhea/nausea, C. difficile infection (CDI). Potential cost-savings from POCTs was assessed by evaluating NICE guideline-referenced POCTs (CRP, FebriDx, Sarasota, FL) as well as a target product profile (TPP).Results: Fifty-percent (7,718,283) of ARI consultations resulted in antibiotics while guideline-based prescribing suggest appropriate antibiotic prescriptions are warranted 9% (1,444,877) of ARI consultations. Direct antibiotic costs for actual ARI consultations associated with antibiotics was £24,003,866 vs. £4,493,568 for guideline-based, "appropriate" antibiotic prescriptions. Antibiotic-related AEs and re-consultations for actual vs. appropriate prescribing totaled £302,496,486 vs. £63,854,269. ARI prescribing plus AE costs totaled £326,729,943 annually without the use of delayed prescribing practices or POCT while the addition of delayed prescribing plus POCT totaled £60,114,564-£78,148,933 depending on the POCT.Conclusions: Adding POCT to outpatient triage of ARI can reduce unnecessary antibiotics and antibiotic-related AEs, resulting in substantial cost savings. Further, near patient diagnostic testing can benefit health systems and patients by avoiding exposure to unnecessary drugs, side effects and antibiotic resistant pathogens.Key points for decision makersMany patients are unnecessarily treated with antibiotics for respiratory infections.Antibiotic misuse leads to unnecessary adverse events, secondary infections, re-consultations, antimicrobial resistance and increased costs.Point-of-care diagnostic tests used to guide antibiotic prescriptions will avoid unnecessary adverse health effects and expenses.

Novel lipoarabinomannan point-of-care tuberculosis test for people with HIV: a diagnostic accuracy study.

BACKGROUND: Most tuberculosis-related deaths in people with HIV could be prevented with earlier diagnosis and treatment. The only commercially available tuberculosis point-of-care test (Alere Determine TB LAM Ag [AlereLAM]) has suboptimal sensitivity, which restricts its use in clinical practice. The novel Fujifilm SILVAMP TB LAM (FujiLAM) assay has been developed to improve the sensitivity of AlereLAM. We assessed the diagnostic accuracy of the FujiLAM assay for the detection of tuberculosis in hospital inpatients with HIV compared with the AlereLAM assay. METHODS: For this diagnostic accuracy study, we assessed biobanked urine samples obtained from the FIND Specimen Bank and the University of Cape Town Biobank, which had been collected from hospital inpatients (aged ≥18 years) with HIV during three independent prospective cohort studies done at two South African hospitals. Urine samples were tested using FujiLAM and AlereLAM assays. The conduct and reporting of each test was done blind to other test results. The primary objective was to assess the diagnostic accuracy of FujiLAM compared with AlereLAM, against microbiological and composite reference standards (including clinical diagnoses). FINDINGS: Between April 18, 2018, and May 3, 2018, urine samples from 968 hospital inpatients with HIV were evaluated. The prevalence of microbiologically-confirmed tuberculosis was 62% and the median CD4 count was 86 cells per µL. Using the microbiological reference standard, the estimated sensitivity of FujiLAM was 70·4% (95% CI 53·0 to 83·1) compared with 42·3% (31·7 to 51·8) for AlereLAM (difference 28·1%) and the estimated specificity of FujiLAM was 90·8% (86·0 to 94·4) and 95·0% (87·7-98·8) for AlereLAM (difference -4·2%). Against the composite reference standard, the specificity of both assays was higher (95·7% [92·0 to 98·0] for FujiLAM vs 98·2% [95·7 to 99·6] for AlereLAM; difference -2·5%), but the sensitivity of both assays was lower (64·9% [50·1 to 76·7] for FujiLAM vs 38·2% [28·1 to 47·3] for AlereLAM; difference 26·7%). INTERPRETATION: In comparison to AlereLAM, FujiLAM offers superior diagnostic sensitivity, while maintaining specificity, and could transform rapid point-of-care tuberculosis diagnosis for hospital inpatients with HIV. The applicability of FujiLAM for settings of intended use requires prospective assessment. FUNDING: Global Health Innovative Technology Fund, UK Department for International Development, Dutch Ministry of Foreign Affairs, Bill & Melinda Gates Foundation, German Federal Ministry of Education and Research, Australian Department of Foreign Affairs and Trade, Wellcome Trust, Department of Science and Technology and National Research Foundation of South Africa, and South African Medical Research Council.

Cost and operational impact of promoting upfront GeneXpert MTB/RIF test referrals for presumptive pediatric tuberculosis patients in India.

BACKGROUND: Outreach and promotion programs are essential to ensuring uptake of new public health interventions and guidelines. We assessed the costs and operation dynamics of outreach and promotion efforts for up front Xpert MTB/RIF (Xpert) testing for pediatric presumptive tuberculosis (TB) patients in four major Indian cities. METHODS: Xpert test costs were assessed as weighted average per-test costs based on the daily workload dynamics matched by test volume specific Xpert unit cost at each study site. Costs of outreach programs to recruit health providers to refer pediatric patients for Xpert testing were assessed as cost per referral for each quarter based on total program costs and referral data. All costs were assessed in the health service provider's perspective and expressed in 2015 USD. RESULTS: Weighted average per-test costs ranged from $14.71 to $17.81 at the four laboratories assessed. Differences between laboratories were associated with unused testing capacity and/or frequencies of overtime work to cope with increasing demand and same-day testing requirements. Outreach activities generated between 825 and 2,065 Xpert testing referrals on average each quarter across the four study sites, translating into $0.63 to $2.55 per patient referred. Overall outreach costs per referral decreased with time, stabilizing at an average cost of $1.10, and demonstrated a clear association with increased referrals. CONCLUSIONS: Xpert test and outreach program costs within and across study sites were mainly driven by the dynamics of Xpert testing demand resulting from the combined outreach activities. However, these increases in demand required considerable overtime work resulting in additional costs and operational challenges at the study laboratories. Therefore, careful laboratory operational adjustment should be evaluated at target areas in parallel to the anticipated demand from the Xpert referral outreach program scale-up in other Indian regions.

Importance of diagnostics in epidemic and pandemic preparedness.

Diagnostics are fundamental for successful outbreak containment. In this supplement, 'Diagnostic preparedness for WHO Blueprint pathogens', we describe specific diagnostic challenges presented by selected priority pathogens most likely to cause future epidemics. Some challenges to diagnostic preparedness are common to all outbreak situations, as highlighted by recent outbreaks of Ebola, Zika and yellow fever. In this article, we review these overarching challenges and explore potential solutions. Challenges include fragmented and unreliable funding pathways, limited access to specimens and reagents, inadequate diagnostic testing capacity at both national and community levels of healthcare and lack of incentives for companies to develop and manufacture diagnostics for priority pathogens during non-outbreak periods. Addressing these challenges in an efficient and effective way will require multiple stakeholders-public and private-coordinated in implementing a holistic approach to diagnostics preparedness. All require strengthening of healthcare system diagnostic capacity (including surveillance and education of healthcare workers), establishment of sustainable financing and market strategies and integration of diagnostics with existing mechanisms. Identifying overlaps in diagnostic development needs across different priority pathogens would allow more timely and cost-effective use of resources than a pathogen by pathogen approach; target product profiles for diagnostics should be refined accordingly. We recommend the establishment of a global forum to bring together representatives from all key stakeholders required for the response to develop a coordinated implementation plan. In addition, we should explore if and how existing mechanisms to address challenges to the vaccines sector, such as Coalition for Epidemic Preparedness Innovations and Gavi, could be expanded to cover diagnostics.

Comparative performance of four rapid Ebola antigen-detection lateral flow immunoassays during the 2014-2016 Ebola epidemic in West Africa.

BACKGROUND: Without an effective vaccine, as was the case early in the 2014-2016 Ebola Outbreak in West Africa, disease control depends entirely on interrupting transmission through early disease detection and prompt patient isolation. Lateral Flow Immunoassays (LFI) are a potential supplement to centralized reference laboratory testing for the early diagnosis of Ebola Virus Disease (EVD). The goal of this study was to assess the performance of commercially available simple and rapid antigen detection LFIs, submitted for review to the WHO via the Emergency Use Assessment and Listing procedure. The study was performed in an Ebola Treatment Centre laboratory involved in EVD testing in Sierra Leone. In light of the current Ebola outbreak in May 2018 in the Democratic Republic of Congo, which highlights the lack of clarity in the global health community about appropriate Ebola diagnostics, our findings are increasingly critical. METHODS: A cross-sectional study was conducted to assess comparative performance of four LFIs for detecting EVD. LFIs were assessed against the same 328 plasma samples and 100 whole EDTA blood samples, using the altona RealStar Filovirus Screen real-time RT-PCR as the bench mark assay. The performance of the Public Health England (PHE) in-house Zaire ebolavirus-specific real time RT-PCR Trombley assay was concurrently assessed. Statistical analysis using generalized estimating equations was conducted to compare LFI performance. FINDINGS: Sensitivity and specificity varied between the LFIs, with specificity found to be significantly higher for whole EDTA blood samples compared to plasma samples in at least 2 LFIs (P≤0.003). Using the altona RT-PCR assay as the bench mark, sensitivities on plasma samples ranged from 79.53% (101/127, 95% CI: 71.46-86.17%) for the DEDIATEST EBOLA (SD Biosensor) to 98.43% (125/127, 95% CI: 94.43-99.81%) for the One step Ebola test (Intec). Specificities ranged from 80.20% (158/197, 95% CI: 74.07-88.60%) for plasma samples using the ReEBOV Antigen test Kit (Corgenix) to 100.00% (98/98, 95% CI: 96.31-100.00%) for whole blood samples using the DEDIATEST EBOLA (SD Biosensor) and SD Ebola Zaire Ag (SD Biosensor). Results also showed the Trombley RT-PCR assay had a lower limit of detection than the altona assay, with some LFIs having higher sensitivity than the altona assay when the Trombley assay was the bench mark. INTERPRETATION: All of the tested EVD LFIs may be considered suitable for use in an outbreak situation (i.e. rule out testing in communities), although they had variable performance characteristics, with none possessing both high sensitivity and specificity. The non-commercial Trombley Zaire ebolavirus RT-PCR assay warrants further investigation, as it appeared more sensitive than the current gold standard, the altona Filovirus Screen RT-PCR assay.

Upfront Xpert MTB/RIF testing on various specimen types for presumptive infant TB cases for early and appropriate treatment initiation.

BACKGROUND: Diagnosis of tuberculosis (TB) in infants is challenging due to non-specific clinical presentations of the disease in this age-group and low sensitivity of widely available TB diagnostic tools, which in turn delays prompt access to TB treatment. Upfront access to Xpert/MTB RIF (Xpert) testing, a highly sensitive and specific rapid diagnostic tool, could potentially address some of these challenges. Under the current project, we assessed the utility and feasibility of applying upfront Xpert for diagnosis of tuberculosis in infants, including for testing of non-sputum specimens. METHODS: A high throughput lab was established in each of the four project cities, and linked to various health care providers across the city, through rapid specimen transportation and electronic reporting linkages. Free Xpert testing was offered to all infant (<2 years of age) presumptive TB cases (both pulmonary and extra-pulmonary) seeking care at public and private health facilities. RESULTS: A total of 7,994 presumptive infant TB cases were enrolled in the project from April 2014 to October 2016, detecting 465 (5.8%, CI: 5.3-6.4) TB cases. The majority (93.9%; CI: 93.4-94.4) of patient specimens were non-sputum and TB positivity was higher amongst non-sputum specimens. Further, a high proportion (5.6% CI 3.8-8.1) of infant TB cases were found to be rifampicin resistant. Covering large cities with a single lab per city over more than two years, the project demonstrated the feasibility of same-day diagnosis with upfront Xpert testing. This in turn led to prompt treatment initiation, with a two-day median turnaround time to treatment initiation. Case mortality observed in the project cohort of diagnosed TB cases was 11.0% (CI 8.4-14.1), the majority of which was pre- or early treatment mortality, in spite of prompt access to treatment for most diagnosed cases. CONCLUSION: The current project demonstrated the feasibility of applying rapid and upfront Xpert testing for presumptive infant TB cases. Rapid TB diagnosis in turn facilitates prompt and appropriate treatment initiation. Further, levels of rifampicin resistance observed in infants TB cases highlight the additional benefit of upfront resistance testing. However, high rates of early case mortality, in spite of prompt diagnosis and treatment initiation, highlight the need for further research in infant patient pathways for overall improvement in TB care for infant populations.

An evaluation framework for new tests that predict progression from tuberculosis infection to clinical disease.

Novel accurate tests are needed that identify individuals infected with Mycobacterium tuberculosis who have incipient disease and are likely to develop clinical tuberculosis (TB) in the near future to allow for targeted preventive treatment beyond the current risk groups. Recently, a target product profile was developed that outlines the minimal and optimal characteristics for such an incipient TB test. We describe an evaluation framework for generating evidence to inform the development of policy guidance for the use of such a new test by the World Health Organization. Two research objectives are addressed. 1) The predictive ability of an incipient TB test should be assessed in clinical evaluation studies that include the intended target population and follow-up of sufficient duration to observe whether individuals do or do not progress to clinical TB disease. 2) Studies are needed to evaluate the test under routine programmatic conditions and measure its impact on patient- or health-system-important outcomes. For both research objectives, study designs, methods and analysis are described, with the intent to inform the clinical development plans of test manufacturers, researchers and funders.

Catalysing progressive uptake of newer diagnostics by health care providers through outreach and education in four major cities of India.

BACKGROUND: Unlike in adults, diagnosis of TB can be challenging in children, as signs and symptoms of paediatric TB can be very non-specific and similar to other common childhood chest infections, which may lead to under or delayed diagnosis of TB disease. In spite of the increasing availability of rapid high-sensitivity diagnostics in public and private sectors, majority of paediatric TB cases are empirically diagnosed, without laboratory confirmation. To address these diagnostic challenges, World Health Organization (WHO) has recommended upfront Xpert MTB/RIF (Xpert) testing for the diagnosis of TB in paediatric presumptive pulmonary and extra-pulmonary TB (EPTB) cases. However, in spite of the increasing availability of rapid high-sensitivity diagnostics, a significant gap exists in its application with Xpert being rarely used as an upfront diagnostic among patients presumed to have TB. Under an ongoing paediatric project since April 2014, which provided free-of-cost upfront Xpert testing, several low-cost outreach and education interventions were undertaken to increase the diagnostic uptake by different providers catering to the paediatric population, thereby increasing adherence to global guidance. METHODS: Providers catering to paediatric population in the project cities were systematically mapped and contacted using different outreach strategies. The focus of outreach efforts was to increase provider literacy and increase their awareness of the availability of free rapid diagnostic services with the goal of changing their diagnostic approaches. RESULTS: From April 2014 to June 2016, more than 5,700 providers/facilities were mapped and 3,670 of them were approached. The number of providers/facilities engaged under the project increased more than 10-fold (43 in April, 2014 to 466 in June, 2016), with significant increase in project uptake, both from public and private sector. Overall 42,238 paediatric presumptive TB cases were enrolled in the project, across the four cities. Over the project period, quarterly diagnostic uptake and paediatric TB cases detection rates increased more than two-fold. TB detection rates were similar in patients from public and private sectors. CONCLUSIONS: Ongoing efforts in scaling up new rapid diagnostics involves significant investments. These efforts need to be complemented with proactive provider engagement to ensure provider-literacy and awareness, for maximizing impact of this scale-up. The current project demonstrated the usefulness of outreach and education interventions for the effective uptake of newer diagnostics.