Rapid, point-of-care diagnosis of tuberculosis with novel Truenat assay: Cost-effectiveness analysis for India's public sector

Health economic evaluations of diagnostic tests for tuberculosis: a narrative review

BACKGROUND

Tuberculosis is the leading cause of death from infectious diseases globally. Non-specific symptoms and limitations of existing diagnostics involve challenges for informed policymaking and clinical practice. This paper reviews common practices in reporting the selection and definition of cost and effect parameters, and in reporting the translation of effect parameters into utility and disability weights, in health economic evaluations of TB diagnostic tests.

METHODS

A targeted literature search in PubMed, Cochrane Library, Web of Science, and Google Scholar identified health economic evaluations of diagnosis and population screening strategies for TB.

RESULTS

We found 28 studies comprising 11 cost-effectiveness and 17 cost-utility analyses. Observed patient data were used in 6 studies, 22 relied solely on model-based evaluations. Variations in prevalence, accuracy, and utility parameters were common, the Consolidated Health Economic Evaluation Reporting Standards terminology for costing was only used in 8 out of 28 studies.

DISCUSSION

Future studies should state the exact type of TB studied, as it can manifest in multiple organs, remain inactive for long periods of time, and since different diagnostics can perform differently depending on the site involved it may influence test accuracies. Additionally, potential impacts of sequential diagnostics on test accuracy and the cost of inaction should receive more attention.

CONCLUSION

Precise terminology and transparent definitions of parameters and methodology in health economics evaluations are necessary to generate evidence that guides policymakers and supports clinical decision-making in the context of TB.

Truenat MTB assays for pulmonary tuberculosis and rifampicin resistance in adults and adolescents

BACKGROUND

Accurate and rapid diagnosis is crucial for ending the tuberculosis epidemic. Truenat assays are World Health Organization (WHO)-recommended rapid molecular diagnostic tests that detect Mycobacterium tuberculosis complex and rifampicin resistance.

OBJECTIVES

Primary objective To assess the diagnostic accuracy of Truenat assays (MTB, MTB Plus, and MTB-RIF Dx) for detecting pulmonary tuberculosis and rifampicin resistance in adults and adolescents with presumptive pulmonary tuberculosis. Secondary objectives To compare the diagnostic accuracy of Truenat assays and Xpert MTB/RIF Ultra for detecting pulmonary tuberculosis and rifampicin resistance and to investigate potential sources of heterogeneity (e.g. HIV status and smear status).

SEARCH METHODS

We searched MEDLINE, Embase, Science Citation Index and Biosis previews, Global Index Medicus, SCOPUS, WHO ICTRP, and ClinicalTrials.gov for published articles and trials in progress on 16and 17 October 2023. We searched ProQuest Dissertations & Theses A&I for dissertations. We contacted tuberculosis experts for ongoing and unpublished studies. A WHO public call for data was made between 30 November 2023 and 15 February 2024.

SELECTION CRITERIA

We included cross-sectional and cohort studies that evaluated Truenat assays in sputum samples from adolescents and adults (aged 10 years and older). The microbiological reference standard for identifying pulmonary tuberculosis is culture. The reference standard for rifampicin resistance is a culture-based drug susceptibility test. Two review authors independently screened titles and abstracts, and assessed the full texts of potentially eligible articles. A third review author resolved any disagreements.

DATA COLLECTION AND ANALYSIS

We tailored and applied the QUADAS-2 and QUADAS-C tools to assess the risk of bias and applicability. Two review authors independently extracted data for each included study, and a third review author resolved any disagreements. We performed meta-analyses to estimate summary sensitivities and specificities using a bivariate model. We assessed the certainty of evidence using the GRADEpro GDT tool.

MAIN RESULTS

Of nine eligible articles, one contributed two distinct participant cohorts, which we considered as separate studies. Thus, we included 10 studies; three assessed Xpert Ultra. Most studies were set in low- and middle-income countries with a high tuberculosis burden. Six studies (4081 participants, 1379 with tuberculosis) assessed Truenat MTB, and four studies (3073 participants, 750 with tuberculosis) assessed Truenat MTB Plus. Two studies (966 participants, 111 with rifampicin resistance) assessed Truenat MTB-RIF Dx. Overall, the risk of bias in the included studies was low. Three of the 10 studies were judged to have high applicability concern in the patient selection domain. Detection of pulmonary tuberculosis The summary sensitivity of Truenat MTB was 87.6% (95% confidence interval (CI) 81.6 to 91.8; high-certainty evidence), and the summary specificity was 86.1% (95% CI 70.1 to 94.3; moderate-certainty evidence). For Truenat MTB Plus, the summary sensitivity was 90.6% (95% CI 83.7 to 94.8; high-certainty evidence), and the summary specificity was 95.7% (95% CI 94.7 to 96.5; high-certainty evidence). Based on the three comparative studies, the summary sensitivity of Truenat MTB was lower (81.0%, 95% CI 72.8 to 87.2) than that of Xpert Ultra (93.7%, 95% CI 90.4 to 95.9), while the summary specificity of Truenat MTB (97.0%, 95% CI 91.9 to 98.9) was marginally higher than Xpert Ultra (95.3%, 95% CI 90.9 to 97.7). Detection of rifampicin resistance The sensitivities from the two studies were 53% and 85% (moderate-certainty evidence) and specificities were both 97% (high-certainty evidence).

AUTHORS' CONCLUSIONS

Truenat MTB Plus had higher sensitivity and specificity than Truenat MTB. The high false-positive rate for Truenat MTB is a concern. The sensitivity of Xpert Ultra was significantly higher than that of Truenat MTB, while specificity was slightly lower. Evidence on the accuracy of Truenat MTB-RIF Dx was limited.

Is health technology assessment value for money? Estimating the return on investment of health technology assessment in India (HTAIn)

An increasing investment in health technology assessment (HTA) in low-income and middle-income countries has generated greater interest from policy-makers about the value and return on investment (ROI) of HTA. Few studies have, however, quantified the benefits of HTA in terms of its value to the health system. This evaluation aims to quantify the impact and ROI achieved by the HTA agency in India (HTAIn).A framework developed by the University of Glasgow was used to review three 'hta's commissioned by HTAIn between 2018 and 2020, taking into account the opportunity cost of investing in these processes. Costs included fixed costs for HTAIn and costs for undertaking each 'hta'. Attributable benefits are calculated by subtracting the counterfactual (benefits that might have been realised without an HTA) from realised benefits.HTAIn sits under the Department of Health Research, Ministry of Health and Family Welfare, Government of India. It was set up to facilitate the process of transparent and evidence-informed decision-making in healthcare in India.HTA helps decision-makers to understand the consequences of alternative courses of action and to select the options that produce the best outcomes at the lowest cost. Institutionalisation of HTA is seen as pivotal to supporting universal health coverage as a means of supporting a better allocation of finite resources, cost containment and the maximisation of health.Net health benefits are our measure of value. The ROI of HTAIn is calculated by aggregating attributable benefits and offsetting them against the costs of investment.Our findings show that investing in HTAIn yields a return of 9:1, with potential to increase to 71:1 with full implementation of HTA recommendations. Variability of ROI ranged from 5:1 to 40:1 between the different interventions and diseases.While HTAIn requires financial investment, it is an efficient use of resources. The potential for greater impact and the variability of the ROI between interventions underline the importance of planning for implementation and good topic selection in HTA.

A Comprehensive Review of the Diagnostics for Pediatric Tuberculosis Based on Assay Time, Ease of Operation, and Performance

Pediatric tuberculosis (TB) is still challenged by several diagnostic bottlenecks, imposing a high TB burden in low- and middle-income countries (LMICs). Diagnostic turnaround time (TAT) and ease of operation to suit resource-limited settings are critical aspects that determine early treatment and influence morbidity and mortality. Based on TAT and ease of operation, this article reviews the evolving landscape of TB diagnostics, from traditional methods like microscopy and culture to cutting-edge molecular techniques and biomarker-based approaches. We examined the benefits of efficient rapid results against potential trade-offs in accuracy and clinical utility. The review highlights emerging molecular methods and artificial intelligence-based detection methods, which offer promising improvements in both speed and sensitivity. The review also addresses the challenges of implementing these technologies in resource-limited settings, where most pediatric TB cases occur. Gaps in the existing diagnostic methods, algorithms, and operational costs were also reviewed. Developing optimal diagnostic strategies that balance speed, performance, cost, and feasibility in diverse healthcare settings can provide valuable insights for clinicians, researchers, and policymakers.

Exploring the perspectives of healthcare workers and Program managers on the use of Truenat as a new tool for TB and DR-TB diagnosis in Nigeria: A qualitative study

BACKGROUND

World Health Organization in the year 2020 recommended the use of Truenat as a replacement for smear microscopy in Tuberculosis (TB) diagnosis and detection of rifampicin resistance. This study was designed to assess enablers and barriers to effective implementation of Truenat assays for TB diagnosis in Nigeria and determine the acceptability of use of Truenat among healthcare workers and TB Program managers in Nigeria.

METHODS

A descriptive exploratory study design was used. Qualitative data were collected via Zoom platform using a pre-tested focus group discussion (FGD) guide and key informant interview (KII) guide. Four FGDs were conducted among Truenat laboratory staff, State Quality Assurance Officers, Local Government Tuberculosis Supervisors and Clinicians working at Truenat sites. Three KIIs were conducted among laboratory leads of Truenat implementing partners and the National TB Control Program.

RESULTS

All the participants attested to the reliability and acceptability of Truenat results, they also highlighted the portability and ease-of-use especially for community outreach testing. Stakeholder engagement, training of Truenat laboratory staff and the perceived low operational cost associated with Truenat were the enablers of Truenat implementation. Major barriers to the implementation included human resource for health constraints, lack of power supply, frequent Trueprep breakdown and Truenat machine connectivity. The same human resource constraint was viewed as the major barrier to scale up of Truenat while employment and retention of Truenat staff coupled with training were seen as the facilitators to scale-up. The participants implored the manufacturers of Truenat to increase the number of modules for Truenat, enable the use of stool for diagnosis of TB and attach a solar panel to the machine.

CONCLUSION

Truenat has gained high acceptance among health workers and TB Program managers in Nigeria. The perceived low operational cost and low infrastructural requirements have been a major boost. There is a need to ensure the retention of health workers especially the Truenat laboratory staff. Training should be sustained including the payment of incentives. Increasing the number of modules of the Truenat machine, enabling the use of stool for TB diagnosis and having a solar panel attached to Truenat machine are essential.

Point-of-Care Diagnosis of Tuberculosis Using a Portable Nucleic Acid Test with Distance-Based Readout

Rapid and accurate diagnosis of tuberculosis (TB) infection in resource-limited settings is critically needed to stop the spread of the disease but remains difficult to achieve. Herein, we report a fast, inexpensive nucleic acid test with distance-based readout (FINDR) for TB. Based on the unique chromatographic behavior of DNA intercalating dye on unmodified cellulose paper, our FINDR platform converted the amplicons of loop-mediated isothermal amplification (LAMP) into the migration distance on a paper-based analytical device. A suite of innovations were further introduced to enhance the accessibility of FINDR, including (1) screening optimal LAMP primers for distance-based readout; (2) developing a chip-on-cover design capable of streamlining LAMP amplification and distance-based detection in a fully sealed FINDR chip with a simple hand-based swirling for liquid transfer; and (3) integrating FINDR with an upstream portable pipetting-free DNA extractor and a downstream smartphone app to simplify sample processing and data interpretation. With these innovations, FINDR demonstrated a high clinical sensitivity (96.6%) and specificity (100%) upon validation against clinical sputum samples. Successful clinical validation was also achieved when FINDR was deployed as a point-of-care test for detecting TB under resource-limited conditions.

Biomarkers in diagnosing and therapeutic monitoring of tuberculosis: a review

Tuberculosis (TB) continues to pose a significant health challenge worldwide, emphasizing the importance of prompt diagnosis and efficient monitoring of treatment outcomes for effective disease control. Biomarkers have become increasingly important in the realm of TB diagnoses and treatment. The objective of this comprehensive review is to examine the present state of biomarkers employed in the diagnosis of TB, monitoring the response to treatment, and predicting treatment outcomes. In this study, we undertake a comprehensive examination of the diverse biomarkers utilized in TB diagnoses, spanning molecular, immunological, and other novel methodologies. Furthermore, we examine the potential of biomarkers in the context of therapeutic monitoring, assessment of treatment effectiveness, and anticipation of drug resistance. Additionally, this paper presents future prospects regarding the utilization of biomarkers in the therapy of tuberculosis.

Cost-effectiveness of diagnostic tools and strategies for the screening and diagnosis of tuberculosis disease and infection: a scoping review

The objective of this scoping review is to understand the cost-effectiveness of current and future tools/strategies for screening and diagnosis of tuberculosis (TB) infection and disease. To this end, PubMed, EMBASE and SCOPUS were used to identify any English language reports on the cost-effectiveness of TB infection/disease screening/diagnostic strategies published between 1 January 2017 and 7 October 2023. Studies included high-burden/risk TB populations, compared diagnostic/screening methods and conducted a cost-effectiveness/economic evaluation. We stratified the included articles in four groups (cost-effectiveness of diagnosing TB disease/infection and cost-effectiveness of screening for TB disease/infection). A full-text review was conducted, and relevant costing data extracted. Of the 2417 articles identified in the initial search, 112 duplicates were removed, and 2305 articles were screened for title and abstract. 23 full articles were reviewed, and 17 fulfilled all inclusion criteria. While sputum smear microscopy (SSM) has been the primary method of diagnosing TB disease in high-burden countries, the current body of literature suggests that SSM is likely to be the least cost-effective tool for the diagnosis of TB disease. Further scale-up with molecular diagnostics, such as GeneXpert and Truenat, was shown to be broadly cost-effective, with a multitest approach likely to be cost-effective for both screening and diagnosis. There is an urgent need to increase access and remove barriers to implementation of diagnostics that have been repeatedly shown to be cost-effective, as well as to develop new diagnostic and screening technologies/strategies to address current barriers to scale-up.

Cost-effectiveness of TB diagnostic technologies in Ethiopia: a modelling study

BACKGROUND

Tuberculosis (TB) is a major threat to public health, particularly in countries where the disease is highly prevalent, such as Ethiopia. Early diagnosis and treatment are the main components of TB prevention and control. Although the national TB guideline recommends the primary use of rapid TB diagnostics whenever feasible, there is limited evidence available that assess the efficiency of deploying various diagnostic tools in the country. Hence, this study aims to evaluate the cost-effectiveness of rapid TB/MDR-TB diagnostic tools in Ethiopia.

METHODS

A hybrid Markov model for a hypothetical adult cohort of presumptive TB cases was constructed. The following TB diagnostic tools were evaluated: X-pert MTB/RIF, Truenat, chest X-ray screening followed by an X-pert MTB/RIF, TB-LAMP, and smear microscopy. Cost-effectiveness was determined based on incremental costs ($) per Disability-adjusted Life Years (DALY) averted, using a threshold of one times Gross Domestic Product (GDP) per capita ($856). Data on starting and transition probabilities, costs, and health state utilities were derived from secondary sources. The analysis is conducted from the health system perspective, and a probabilistic sensitivity analysis is performed.

RESULT

The incremental cost-effectiveness ratio for X-pert MTB/RIF, compared to the next best alternative, is $276 per DALY averted, making it a highly cost-effective diagnostic tool. Additionally, chest X-ray screening followed an X-pert MTB/RIF test is less cost-effective, with an ICER of $1666 per DALY averted. Introducing X-pert MTB/RIF testing would enhance TB detection and prevent 9600 DALYs in a cohort of 10,000 TB patients, with a total cost of $3,816,000.

CONCLUSION

The X-pert MTB/RIF test is the most cost-effective diagnostic tool compared to other alternatives. The use of this diagnostic tool improves the early detection and treatment of TB cases. Increased funding for this diagnostic tool will enhance access, reduce the TB detection gaps, and improve treatment outcomes.

Finding the missed millions: innovations to bring tuberculosis diagnosis closer to key populations

Current strategies to promptly, effectively, and equitably screen people with tuberculosis (TB) and link them to diagnosis and care are insufficient; new approaches are required to find the millions of people around the world with TB who are missed each year. Interventions also need to be designed considering how people interact with health care facilities and where appropriate should be suitable for use in the community. Here, the historical, new, and reemerging technologies that are being utilised for TB diagnosis globally are discussed, whilst highlighting that how we use and evaluate tests is just as important as the tests themselves.

Diagnostic precision of Truenat® technique and co-relation of ALT levels with HBV-DNA viral load among HBsAg positive patients at a tertiary care hospital in Eastern Uttar Pradesh

Background and Objectives

In India, it is estimated that there are 40 million people suffering from Hepatitis B virus (HBV). Quantification of the viral burden is an important laboratory tool in the management. However, widespread use of different HBV-DNA assays is still affected by the high cost and variable diagnostic precision. The present study was conducted to evaluate the diagnostic precision and co-relation of ALT levels with HBV-DNA by Truenat®-PCR.

Materials and Methods

In this prospective cross-sectional study a total of 567 serums were collected from patients by rapid HBsAg, and processed for liver function tests (LFT). The viral HBV-DNA amplification detection was carried out through by Truenat®-PCR test.

Results

Out of 567 samples, 452 samples were found to be positive by both rapid and Truenat®-PCR and 106 were negative for HBV-DNA followed by 9 invalid. High ALT level found in 73% of positive patients who had HBV-DNA level (>100000 copies/ml) which is significantly higher in 447 patients as compared to those have below ≤100000 copies/ml.

Conclusion

Truenat®-PCR technique is a highly sensitive and can be performed with low resources for effective control of HBV infection. Evaluation of HBV-DNA levels and serum ALT levels showed a significant proportion of patient harbored ongoing viral replication and disease progression.

Rapid Detection of M. tuberculosis and Its Resistance to Rifampicin and Isoniazid with the mfloDx™ MDR-TB test

BACKGROUND

Rapid detection of tuberculosis (TB) and its resistance are essential for the prompt initiation of correct drug therapy and for stopping the spread of drug-resistant TB. There is an urgent need for increased use of rapid diagnostic tests to control the threat of increased TB and multidrug-resistant TB (MDR-TB).

METHODS

EMPE Diagnostics has developed a multiplex molecular diagnostic platform called mfloDx™ by combining nucleotide-specific padlock probe-dependent rolling circle amplification with sensitive lateral flow biosensors, providing visual signals, similar to a COVID-19 test. The first test kit of this platform, mfloDx™ MDR-TB can identify Mycobacterium tuberculosis (MTB) complex and its clinically significant mutations in the rpoB and katG genes and in the inhA promotor contributing resistance to rifampicin (RIF) and isoniazid (INH), causing MDR-TB.

RESULTS

We have evaluated the performance of the mfloDx™ MDR-TB test on 210 sputum samples (110 from suspected TB cases and 100 from TB-negative controls) received from a tertiary care center in India. The clinical sensitivity for detecting MTB compared to acid-fast microscopy and mycobacteria growth indicator tube (MGIT) cultures was 86.4% and 84.9%, respectively. All the 100 control samples were negative indicating excellent specificity. In smear-positive sputum samples, the mfloDx™ MDR-TB test showed a sensitivity of 92.5% and 86.4% against MGIT culture and Xpert MTB/RIF, respectively. The clinical sensitivity for the detection of RIF and INH resistance in comparison with MGIT drug susceptibility testing was 100% and 84.6%, respectively, while the clinical specificity was 100%.

CONCLUSION

From the above evaluation, we find mfloDx™ MDR-TB to be a rapid and efficient test to detect TB and its multidrug resistance in 3 h at a low cost making it suitable for resource-limited laboratories.

Advanced HIV disease: A review of diagnostic and prophylactic strategies

BACKGROUND

Despite expanded access to antiretroviral therapy (ART) and the rollout of the World Health Organization's (WHO) 'test-and-treat' strategy, the proportion of people with HIV (PWH) presenting with advanced HIV disease (AHD) remains unchanged at approximately 30%. Fifty percent of persons with AHD report prior engagement to care. ART failure and insufficient retention in HIV care are major causes of AHD. People living with AHD are at high risk for opportunistic infections and death. In 2017, the WHO published guidelines for the management of AHD that included a comprehensive package of care for screening and prophylaxis of major opportunistic infections (OIs). In the interim, ART regimens have evolved: integrase inhibitors are first-line therapy globally, and the diagnostic landscape is evolving. The objective of this review is to highlight novel point-of-care (POC) diagnostics and treatment strategies that can facilitate OI screening and prophylaxis for persons with AHD.

METHODS

We reviewed the WHO guidelines for recommendations for persons with AHD. We summarized the scientific literature on current and emerging diagnostics, along with emerging treatment strategies for persons with AHD. We also highlight the key research and implementation gaps together with potential solutions.

RESULTS

While POC CD4 testing is being rolled out in order to identify persons with AHD, this alone is insufficient; implementation of the Visitect CD4 platform has been challenging given operational and test interpretation issues. Numerous non-sputum POC TB diagnostics are being evaluated, many with limited sensitivity. Though imperfect, these tests are designed to provide rapid results (within hours) and are relatively affordable for resource-poor settings. While novel POC diagnostics are being developed for cryptococcal infection, histoplasmosis and talaromycosis, implementation science studies are urgently needed to understand the clinical benefit of these tests in the routine care.

CONCLUSIONS

Despite progress with HIV treatment and prevention, a persistent 20%-30% of PWH present to care with AHD. Unfortunately, these persons with AHD continue to carry the burden of HIV-related morbidity and mortality. Investment in the development of additional POC or near-bedside CD4 platforms is urgently needed. Implementation of POC diagnostics theoretically could improve HIV retention in care and thereby reduce mortality by overcoming delays in laboratory testing and providing patients and healthcare workers with timely same-day results. However, in real-world scenarios, people with AHD have multiple comorbidities and imperfect follow-up. Pragmatic clinical trials are needed to understand whether these POC diagnostics can facilitate timely diagnosis and treatment, thereby improving clinical outcomes such as HIV retention in care.

The Value-of-Information and Value-of-Implementation from Clinical Trials of Diagnostic Tests for HIV-Associated Tuberculosis: A Modeling Analysis

Objectives. Conventional value-of-information (VOI) analysis assumes complete uptake of an optimal decision. We employed an extended framework that includes value-of-implementation (VOM)-the benefit of encouraging adoption of an optimal strategy-and estimated how future trials of diagnostic tests for HIV-associated tuberculosis could improve public health decision making and clinical and economic outcomes. Methods. We evaluated the clinical outcomes and costs, given current information, of 3 tuberculosis screening strategies among hospitalized people with HIV in South Africa: sputum Xpert (Xpert), sputum Xpert plus urine AlereLAM (Xpert+AlereLAM), and sputum Xpert plus the newer, more sensitive, and costlier urine FujiLAM (Xpert+FujiLAM). We projected the incremental net monetary benefit (INMB) of decision making based on results of a trial comparing mortality with each strategy, rather than decision making based solely on current knowledge of FujiLAM's improved diagnostic performance. We used a validated microsimulation to estimate VOI (the INMB of reducing parameter uncertainty before decision making) and VOM (the INMB of encouraging adoption of an optimal strategy). Results. With current information, adopting Xpert+FujiLAM yields 0.4 additional life-years/person compared with current practices (assumed 50% Xpert and 50% Xpert+AlereLAM). While the decision to adopt this optimal strategy is unaffected by information from the clinical trial (VOI = $ 0 at $3,000/year-of-life saved willingness-to-pay threshold), there is value in scaling up implementation of Xpert+FujiLAM, which results in an INMB (representing VOM) of $650 million over 5 y. Conclusions. Conventional VOI methods account for the value of switching to a new optimal strategy based on trial data but fail to account for the persuasive value of trials in increasing uptake of the optimal strategy. Evaluation of trials should include a focus on their value in reducing barriers to implementation.

Highlights

In conventional VOI analysis, it is assumed that the optimal decision will always be adopted even without a trial. This can potentially lead to an underestimation of the value of trials when adoption requires new clinical trial evidence. To capture the influence that a trial may have on decision makers' willingness to adopt the optimal decision, we also consider value-of-implementation (VOM), a metric quantifying the benefit of new study information in promoting wider adoption of the optimal strategy. The overall value-of-a-trial (VOT) includes both VOI and VOM.Our model-based analysis suggests that the information obtained from a trial of screening strategies for HIV-associated tuberculosis in South Africa would have no value, when measured using traditional methods of VOI assessment. A novel strategy, which includes the urine FujiLAM test, is optimal from a health economic standpoint but is underutilized. A trial would reduce uncertainties around downstream health outcomes but likely would not change the optimal decision. The high VOT (nearly $700 million over 5 y) lies solely in promoting uptake of FujiLAM, represented as VOM.Our results highlight the importance of employing a more comprehensive approach for evaluating prospective trials, as conventional VOI methods can vastly underestimate their value. Trialists and funders can and should assess the VOT metric instead when considering trial designs and costs. If VOI is low, the VOM and cost of a trial can be compared with the benefits and costs of other outreach programs to determine the most cost-effective way to improve uptake.

Expedited diagnosis of pediatric tuberculosis using Truenat MTB-Rif Dx and GeneXpert MTB/RIF

Rapid, cost-effective, and sensitive diagnostic assays are essential for global tuberculosis (TB) control, especially in high TB burden, resource-limited settings. The current study was designed to evaluate diagnostic accuracy of Truenat MTB-Rif Dx (MolBio) in children less than 18 years of age, with symptoms suggestive of TB. Gastric aspirate, induced sputum, and broncho-alveolar lavage samples were subjected simultaneously to AFB-smear, GeneXpert MTB/RIF, liquid culture (MGIT-960) and Truenat MTB-Rif Dx. The index-test results were evaluated against microbiological reference standards (MRS). Truenat MTB-Rif Dx had a sensitivity of 57.1%, specificity of 92% against MRS. The sensitivity and specificity of the Truenat MTB-RIF Dx compared with liquid culture was 58.7% and 87.5% while GeneXpert MTB/RIF was 56% and 91.4%. The performance of both GeneXpert MTB/RIF and Truenat MTB-Rif Dx are comparable. Result of our study demonstrates that Truenat MTB-Rif can aid in early and efficient diagnosis of TB in children.

Cochrane Infectious Diseases Group, Inbaraj LR, Daniel J, Rajendran P, Bhaskar A, Srinivasalu VA, Narayanan MKS, Shewade HD, Kirubakaran R, Scandrett K, Malaisamy M, Takwoingi Y, Padmapriyadarsini C. Truenat MTB assays for pulmonary tuberculosis and rifampicin resistance in adults

This is a protocol for a Cochrane Review (diagnostic). The objectives are as follows:

To determine the diagnostic accuracy of Truenat assays (MTB, MTB Plus, and MTB RIF Dx) for detecting pulmonary tuberculosis and rifampicin resistance in adults with presumptive pulmonary tuberculosis.

Cost-Effectiveness of Currently Available Diagnostic Tools for Diagnosis of Pediatric Tuberculosis Under National Tuberculosis Elimination Program

In India, children do not get diagnosed with tuberculosis (TB) for reasons such as lack of screening modality at the health-care settings, inadequate sputum sample, and low detection rate. This study aims to assess various modalities for diagnosis of pediatric TB and their cost-effectiveness. Cost-effectiveness was found for various diagnostic modalities for TB diagnosis in children of India below 15 years of age. TrueNat MTB was the intervention being compared to GeneXpert MTB and sputum microscopy. Evidence pertinent to effectiveness and cost per test, and health benefits in terms of disability adjusted life years were researched and documented. Modeling a cohort of children through a decision tree and assimilating costs and disability-adjusted life years (DALYs) at each step gave results in the form of cost-effectiveness. Interventions were compared by calculating the cost-effectiveness ratio. The results revealed that TrueNat is more cost effective (Rs. 9450/DALY averted) compared to GeneXpert MTB/RIF (Rs. 9750/DALY averted). The incremental cost effectiveness ratio of TrueNat with respect to GeneXpert was found to be Rs. 5925 per DALY averted. Diagnosis through TrueNat point of care (POC) will avert 962 more DALYs compared to GeneXpert. As is evident from the results, TrueNat does alleviate disability caused by TB in children as more DALYs are averted. At an additional cost of Rs. 5925 to avert one DALY, which is below the gross domestic product (GDP) per capita for India (for 2021, it was $2277), TrueNat can have significant health benefits.

Diagnostic biomarkers for active tuberculosis: progress and challenges

Tuberculosis (TB) is a leading cause of morbidity and mortality from a single infectious agent, despite being preventable and curable. Early and accurate diagnosis of active TB is critical to both enhance patient care, improve patient outcomes, and break Mycobacterium tuberculosis (Mtb) transmission cycles. In 2020 an estimated 9.9 million people fell ill from Mtb, but only a little over half (5.8 million) received an active TB diagnosis and treatment. The World Health Organization has proposed target product profiles for biomarker- or biosignature-based diagnostics using point-of-care tests from easily accessible specimens such as urine or blood. Here we review and summarize progress made in the development of pathogen- and host-based biomarkers for active TB diagnosis. We describe several unique patient populations that have posed challenges to development of a universal diagnostic TB biomarker, such as people living with HIV, extrapulmonary TB, and children. We also review additional limitations to widespread validation and utilization of published biomarkers. We conclude with proposed solutions to enhance TB diagnostic biomarker validation and uptake.

Diagnostic Accuracy of the Truenat MTB Plus Assay and Comparison with the Xpert MTB/RIF Assay to Detect Tuberculosis among Hospital Outpatients in Cameroon

The Truenat MTB Plus assay is a rapid molecular test that has been recommended by the World Health Organization since 2020 as an initial test to detect tuberculosis (TB). The WHO highlighted the need to further evaluate assay performance to inform future recommendations, including in people living with HIV and compared to the Xpert MTB/RIF assay. We conducted a prospective evaluation of the diagnostic accuracy of the Truenat assay in Cameroon, a country with a high burden of HIV/TB. Adult outpatients were recruited at four hospitals; demographic information and medical history were collected, and participants produced two sputum specimens. Truenat and Xpert testing was performed on the same specimen, and performance was compared to TB culture as the reference standard. From November 2019 to December 2020, 945 participants were enrolled and included in the analysis. Among 251 participants with culture-positive TB, the sensitivity of Truenat MTB Plus was 91% (95% confidence interval [CI], 86 to 94%), similar to Xpert (90%; 95% CI, 86 to 93%). Among 74 HIV-positive participants with culture-positive TB, the sensitivity of Truenat MTB Plus was 85% (95% CI, 75 to 92%) compared to 81% for Xpert (95% CI, 70 to 89%). Among 47 participants with smear-negative TB, the sensitivity of Truenat MTB Plus was 55% (95% CI, 40 to 70%), similar to Xpert (53%; 95% CI, 38 to 68%). The specificity of Truenat MTB Plus was 96% (95% CI, 94 to 97%) compared to 99% (95% CI, 97 to 99%) for Xpert. For TB detection compared to the reference standard of TB culture, the performance of the Truenat MTB Plus assay was similar to that of Xpert in this population, including among people living with HIV.

Determining the lower limit of detection required for HCV viral load assay for test of cure following direct-acting antiviral-based treatment regimens: Evidence from a global data set

Achieving global elimination of hepatitis C virus requires a substantial scale-up of testing. Point-of-care HCV viral load assays are available as an alternative to laboratory-based assays to promote access in hard to reach or marginalized populations. The diagnostic performance and lower limit of detection are important attributes of these new assays for both diagnosis and test of cure. Therefore, our objective was to determine an acceptable LLoD for detectable HCV viraemia as a test for cure, 12 weeks post-treatment (SVR12). We assembled a global data set of patients with detectable viraemia at SVR12 from observational databases from 9 countries (Egypt, the United States, United Kingdom, Georgia, Ukraine, Myanmar, Cambodia, Pakistan, Mozambique) and two pharmaceutical-sponsored clinical trial registries. We examined the distribution of HCV viral load at SVR12 and presented the 90th, 95th, 97th and 99th percentiles. We used logistic regression to assess characteristics associated with low-level virological treatment failure (defined as <1000 IU/mL). There were 5973 cases of detectable viraemia at SVR12 from the combined data set. Median detectable HCV RNA at SVR12 was 287,986 IU/mL. The level of detection for the 95th percentile was 227 IU/mL (95% CI 170-276). Females and those with minimal fibrosis were more likely to experience low-level viraemia at SVR12 compared to men (adjusted odds ratio AOR = 1.60 95% confidence interval [CI] 1.30-1.97 and those with cirrhosis (AOR = 1.49 95% CI 1.15-1.93). In conclusion, an assay with a level of detection of 1000 IU/mL or greater may miss a proportion of those with low-level treatment failure.

Point-of-care diagnostic tests for tuberculosis disease

Rapid diagnosis is one key pillar to end tuberculosis (TB). Point-of-care tests (POCTs) facilitate early detection, immediate treatment, and reduced transmission of TB disease. This Review evaluates current diagnostic assays endorsed by the World Health Organization and identifies the gaps between existing conventional tests and the ideal POCT. We discuss the commercial development of new rapid tests and research studies on nonsputum-based diagnostic biomarkers from both pathogen and host. Last, we highlight advances in integrated microfluidics technology that may aid the development of new POCTs.

Economic Analyses of Respiratory Tract Infection Diagnostics: A Systematic Review

BACKGROUND

Diagnostic testing for respiratory tract infections is a tool to manage the current COVID-19 pandemic, as well as the rising incidence of antimicrobial resistance. At the same time, new European regulations for market entry of in vitro diagnostics, in the form of the in vitro diagnostic regulation, may lead to more clinical evidence supporting health-economic analyses.

OBJECTIVE

The objective of this systematic review was to review the methods used in economic evaluations of applied diagnostic techniques, for all patients seeking care for infectious diseases of the respiratory tract (such as pneumonia, pulmonary tuberculosis, influenza, sinusitis, pharyngitis, sore throats and general respiratory tract infections).

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, articles from three large databases of scientific literature were included (Scopus, Web of Science and PubMed) for the period January 2000 to May 2020.

RESULTS

A total of 70 economic analyses are included, most of which use decision tree modelling for diagnostic testing for respiratory tract infections in the community-care setting. Many studies do not incorporate a generally comparable clinical outcome in their cost-effectiveness analysis: fewer than half the studies (33/70) used generalisable outcomes such as quality-adjusted life-years. Other papers consider outcomes related to the accuracy of the test or outcomes related to the prescribed treatment. The time horizons of the studies generally are limited.

CONCLUSIONS

The methods to economically assess diagnostic tests for respiratory tract infections vary and would benefit from clear recommendations from policy makers on the assessed time horizon and outcomes used.

Engaging with the private healthcare sector for the control of tuberculosis in India: cost and cost-effectiveness

Background

The control of tuberculosis (TB) in India is complicated by the presence of a large, disorganised private sector where most patients first seek care. Following pilots in Mumbai and Patna (two major cities in India), an initiative known as the ‘Public–Private Interface Agency’ (PPIA) is now being expanded across the country. We aimed to estimate the cost-effectiveness of scaling up PPIA operations, in line with India’s National Strategic Plan for TB control.

Methods

Focusing on Mumbai and Patna, we collected cost data from implementing organisations in both cities and combined this data with models of TB transmission dynamics. Estimating the cost per disability adjusted life years (DALY) averted between 2014 (the start of PPIA scale-up) and 2025, we assessed cost-effectiveness using two willingness-to-pay approaches: a WHO-CHOICE threshold based on per-capita economic productivity, and a more stringent threshold incorporating opportunity costs in the health system.

Findings

A PPIA scaled up to ultimately reach 50% of privately treated TB patients in Mumbai and Patna would cost, respectively, US$228 (95% uncertainty interval (UI): 159 to 320) per DALY averted and US$564 (95% uncertainty interval (UI): 409 to 775) per DALY averted. In Mumbai, the PPIA would be cost-effective relative to all thresholds considered. In Patna, if focusing on adherence support, rather than on improved diagnosis, the PPIA would be cost-effective relative to all thresholds considered. These differences between sites arise from variations in the burden of drug resistance: among the services of a PPIA, improved diagnosis (including rapid tests with genotypic drug sensitivity testing) has greatest value in settings such as Mumbai, with a high burden of drug-resistant TB.

Conclusions

To accelerate decline in TB incidence, it is critical first to engage effectively with the private sector in India. Mechanisms such as the PPIA offer cost-effective ways of doing so, particularly when tailored to local settings.

Mobile digital x-ray and portable cartridge based nucleic acid amplification test machines for point-of-care diagnosis of TB in rural India

BACKGROUND

There is no experience of point-of-care (POC) microbiological confirmation for TB in India in field settings.

METHODS

Under the TB-Free Haryana project, a mobile van-mounted digital x-ray and portable GeneXpert system screened all presumptive TB patients with strong clinic-radiological suspicion for TB.

RESULTS

Of 1673 x-rays, 215 (13%) had findings suggestive of TB, 109 had strong clinical suspicion and were eligible for POC GeneXpert, in whom a test was performed in 82 (75%) cases; 59 (72%) tested positive and were initiated on treatment within 24 h.

CONCLUSIONS

A mobile van equipped with digital x-ray and POC GeneXpert is feasible and has a good success rate with potential for replication.

Active support after natural disasters: a review of a microbiologist's role

In the aftermath of a natural disaster, multispecialty rapid response teams are deployed to support health-related relief work. Microbiologists are often part of such teams, along with public health specialists, clinicians and entomologists, and can contribute to the response in multiple ways. The role of a microbiologist is critical not only for laboratory diagnosis of infectious diseases, but also for situational analysis and evaluation, planning, prevention and control. The task begins with risk assessment, specifically for identification of diseases epidemic and endemic to the area. Evaluation of existing laboratory setups and establishment of services where none exist is a priority, including facilitation of a tiered laboratory system. Training of laboratory staff at short notice in field settings, biosafety and biomedical waste management are niche areas where microbiologists can contribute. Emerging focus areas include establishment of modular laboratories, infection prevention and control in community evacuation centres and considerations for reopening of healthcare facilities closed due to extensive natural damage. A trained and efficient microbiologist will prove a valuable asset to provide timely and useful support for infectious disease diagnosis, prevention, control and management in the wake of natural disasters.

Health Economic Evidence of Point-of-Care Testing: A Systematic Review

OBJECTIVE

Point-of-care testing (POCT) has become an essential diagnostic technology for optimal patient care. Its implementation, however, still falls behind. This paper reviews the available evidence on the health economic impact of introducing POCT to assess if poor POCT uptake may be related to lacking evidence.

STUDY DESIGN

The Scopus and PubMed databases were searched to identify publications describing a health economic evaluation of a point-of-care (POC) test. Data were extracted from the included publications, including general and methodological characteristics as well as the study results summarized in either cost, effects or an incremental cost-effectiveness ratio. Results were sorted into six groups according to the POC test's purpose (diagnosis, screening or monitoring) and care setting (primary care or secondary care). The reporting quality of the publications was determined using the CHEERS checklist.

RESULTS

The initial search resulted in 396 publications, of which 44 met the inclusion criteria. Most of the evaluations were performed in a primary care setting (n = 31; 70.5%) compared with a secondary care setting (n = 13; 29.5%). About two thirds of the evaluations were on POC tests implemented with a diagnostic purpose (n = 28; 63.6%). More than 75% of evaluations concluded that POCT is recommended for implementation, although in some cases only under specific circumstances and conditions. Compliance with the CHEERS checklist items ranged from 20.8% to 100%, with an average reporting quality of 72.0%.

CONCLUSION

There were very few evaluations in this review that advised against the implementation of POCT. However, the uptake of POCT in many countries remains low. Even though the evaluations included in this review did not always include the full long-term benefits of POCT, it is clear that health economic evidence across a few dimensions of value already indicate the benefits of POCT. This suggests that the lack of evidence on POCT is not the primary barrier to its implementation and that the low uptake of these tests in clinical practice is due to (a combination of) other barriers. In this context, aspects around organization of care, support of clinicians and quality management may be crucial in the widespread implementation of POCT.

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 performance of point-of-care Truenat assays in primary healthcare centres is comparable to that of Xpert MTB/RIF placed in reference laboratories. The WHO now recommends Truenat as an initial test for detection of TB and RIF resistance.https://bit.ly/31Wj3S6

Current updates in diagnosis of male urogenital tuberculosis

Introduction: Urogenital tuberculosis (UGTB) is a common manifestation of extrapulmonary TB (EPTB), which affects both men and women in a ratio of 2:1. Similar to other EPTB types, diagnosis of UGTB is quite challenging owing to atypical clinical presentation and paucibacillary nature of specimens. This review is primarily focused on the current updates developed in the diagnosis of male UGTB.Area covered: Smear/culture, imaging, histopathology, and interferon-γ release assays are the main modalities employed for detecting male UGTB cases. Moreover, we described the utility of nucleic acid amplification tests (NAATs), including loop-mediated isothermal amplification, PCR, nested-PCR, and GeneXpert (MTB/RIF) assays. The possibility of using other novel modalities, such as immuno-PCR (I-PCR), aptamer-linked immobilized sorbent assay (ALISA), and identification of circulating cell-free DNA (cfDNA) by NAATs were also discussed.Expert opinion: The current methods used for the diagnosis of male UGTB are not adequate. Therefore, the latest molecular/immunological tools, i.e. Xpert Ultra, Truenat MTB^TM, I-PCR, ALISA, and cfDNA detection employed for the diagnosis of other EPTB forms and pulmonary TB may also be exploited for UGTB diagnosis. Reliable and timely diagnosis of male UGTB may initiate an early start of anti-tubercular therapy that would reduce infertility and other complications associated with disease.

Multicentric validation of indigenous molecular test Truenat™ MTB for detection of Mycobacterium tuberculosis in sputum samples from presumptive pulmonary tuberculosis patients in comparison with reference standards

Background & objectives:

Early case detection is essential to interrupt transmission and to prevent further spread of tuberculosis (TB) in high endemic settings. Nucleic acid amplification tests (NAATs) with visual read-outs are ideal as point-of-care tests. Truenat™ MTB is an indigenous chip-based NAAT for detection of Mycobacterium tuberculosis, which involves extraction of DNA and real-time polymerase chain reaction (PCR) using portable, automated, battery-operated instruments. The current multicentric study was aimed to evaluate Truenat for detection of MTB in sputum samples obtained from patients with presumptive pulmonary TB with reference to culture as gold standard and Xpert as a comparator.

Methods:

The study was conducted at four sites, namely ICMR-National Institute for Research in Tuberculosis, Chennai; All India Institute of Medical Sciences, New Delhi; ICMR-National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Agra; and National Institute of TB and Respiratory Diseases, New Delhi. Patients suspected to have TB were screened for eligibility. Two sputum samples were collected from each patient. Tests included smear, Xpert and Truenat directly from the sputum sample and culture by Lowenstein-Jensen (L-J) medium and MGIT960 from decontaminated pellets. Sample used for Truenat assay was coded. Resolution of Truenat false positives was done using an in-house PCR with TRC₄ primers.

Results:

The study enrolled 2419 presumptive TB patients after screening 2465 patients, and 3541 sputum samples were collected from the enrolled patients. Results of 2623 samples were available for analysis. Truenat showed a positivity rate of 48.5 per cent as compared to 37.0 per cent by Xpert. The sensitivities of Truenat and Xpert were was 88.3 and 79.7 per cent, respectively in comparison with culture.

Interpretation & conclusions:

Truenat MTB identified more positives among culture-confirmed samples than Xpert and had higher sensitivity. In addition, other advantageous operational features of Truenat MTB were identified which would be useful in field settings.

Controlling the drug-resistant tuberculosis epidemic in India: challenges and implications

India has a higher tuberculosis (TB) burden than any other country, accounting for an estimated one-fourth of the global burden. Drug-resistant tuberculosis (DR-TB) presents a major public health problem in India. Patients with DR-TB often require profound changes in their drug regimens, which are invariably linked to poor treatment adherence and sub-optimal treatment outcomes compared to drug-sensitive TB. The challenge of addressing DR-TB is critical for India, as India contributes over 27% of global DR-TB cases. In recent decades, India has been proactive in its battle against TB, even implementing a revised National Strategic Plan to eliminate TB by 2025. However, to achieve this ambitious goal, the country will need to take a multifaceted approach with respect to its management of DR-TB. Despite concerted efforts made by the National TB Elimination Program, India faces substantial challenges with regard to DR-TB care, especially in peripheral and resource-limited endemic zones. This article describes some of the major challenges associated with mitigating the growing DR-TB epidemic in India and their implications.

Comparative Performance of Line Probe Assay (Version 2) and Xpert MTB/RIF Assay for Early Diagnosis of Rifampicin-Resistant Pulmonary Tuberculosis

BACKGROUND

The emergence of drug-resistant tuberculosis (TB), is a major menace to cast off TB worldwide. Line probe assay (LPA; GenoType MTBDRplus ver. 2) and Xpert MTB/RIF assays are two rapid molecular TB detection/diagnostic tests. To compare the performance of LPA and Xpert MTB/RIF assay for early diagnosis of rifampicin-resistant (RR) TB in acid-fast bacillus (AFB) smear-positive and negative sputum samples.

METHODS

A total 576 presumptive AFB patients were selected and subjected to AFB microscopy, Xpert MTB/RIF assay and recent version of LPA (GenoType MTBDRplus assay version 2) tests directly on sputum samples. Results were compared with phenotypic culture and drug susceptibility testing (DST). DNA sequencing was performed with rpoB gene for samples with discordant rifampicin susceptibility results.

RESULTS

Among culture-positive samples, Xpert MTB/RIF assay detected Mycobacterium tuberculosis (Mtb) in 97.3% (364/374) of AFB smear-positive samples and 76.5% (13/17) among smear-negative samples, and the corresponding values for LPA test (valid results with Mtb control band) were 97.9% (366/374) and 58.8% (10/17), respectively. For detection of RR among Mtb positive molecular results, the sensitivity of Xpert MTB/RIF assay and LPA (after resolving discordant phenotypic DST results with DNA sequencing) were found to be 96% and 99%, respectively. Whereas, specificity of both test for detecting RR were found to be 99%.

CONCLUSION

We conclude that although Xpert MTB/RIF assay is comparatively superior to LPA in detecting Mtb among AFB smear-negative pulmonary TB. However, both tests are equally efficient in early diagnosis of AFB smear-positive presumptive RR-TB patients.

Multi-drug resistant tuberculosis, ten years later

Drug-resistant tuberculosis, especially those with resistance to rifampicin (RR-TB), has become one of the main obstacles to achieving the dream of eradicating tuberculosis. Furthermore, it is necessary to combine three or four different drugs in the attempt to cure TB, however, unfortunately, there are few available that can be considered genuinely effective. Fortunately, the notable worldwide increase in RR-TB in recent years has led to the investment of resources in the development of new drugs for TB, and other drugs investigated for other diseases have been successfully tested on TB. This has resulted in a clear change in the clinical management of these patients over the last 3-4 years, and it is now easier to design therapeutic regimens and achieve higher success rates. All these changes are updated in this review.

Trade-offs between cost and accuracy in active case finding for tuberculosis: A dynamic modelling analysis

BACKGROUND

Active case finding (ACF) may be valuable in tuberculosis (TB) control, but questions remain about its optimum implementation in different settings. For example, smear microscopy misses up to half of TB cases, yet is cheap and detects the most infectious TB cases. What, then, is the incremental value of using more sensitive and specific, yet more costly, tests such as Xpert MTB/RIF in ACF in a high-burden setting?

METHODS AND FINDINGS

We constructed a dynamic transmission model of TB, calibrated to be consistent with an urban slum population in India. We applied this model to compare the potential cost and impact of 2 hypothetical approaches following initial symptom screening: (i) 'moderate accuracy' testing employing a microscopy-like test (i.e., lower cost but also lower accuracy) for bacteriological confirmation and (ii) 'high accuracy' testing employing an Xpert-like test (higher cost but also higher accuracy, while also detecting rifampicin resistance). Results suggest that ACF using a moderate-accuracy test could in fact cost more overall than using a high-accuracy test. Under an illustrative budget of US$20 million in a slum population of 2 million, high-accuracy testing would avert 1.14 (95% credible interval 0.75-1.99, with p = 0.28) cases relative to each case averted by moderate-accuracy testing. Test specificity is a key driver: High-accuracy testing would be significantly more impactful at the 5% significance level, as long as the high-accuracy test has specificity at least 3 percentage points greater than the moderate-accuracy test. Additional factors promoting the impact of high-accuracy testing are that (i) its ability to detect rifampicin resistance can lead to long-term cost savings in second-line treatment and (ii) its higher sensitivity contributes to the overall cases averted by ACF. Amongst the limitations of this study, our cost model has a narrow focus on the commodity costs of testing and treatment; our estimates should not be taken as indicative of the overall cost of ACF. There remains uncertainty about the true specificity of tests such as smear and Xpert-like tests in ACF, relating to the accuracy of the reference standard under such conditions.

CONCLUSIONS

Our results suggest that cheaper diagnostics do not necessarily translate to less costly ACF, as any savings from the test cost can be strongly outweighed by factors including false-positive TB treatment, reduced sensitivity, and foregone savings in second-line treatment. In resource-limited settings, it is therefore important to take all of these factors into account when designing cost-effective strategies for ACF.

Guidelines for Preoperative Testing for Neurosurgery in Coronavirus Disease 2019 (COVID-19) Era: Indian Viewpoint Amidst Global Practice

Preoperative testing and evaluation for coronavirus disease 2019 (COVID-19) have been an enigmatic challenge for the neurosurgical community during the pandemic. Since the beginning of the pandemic, laboratory diagnostic methods have evolved substantially, and with them has been the necessity for readily available, fast, and accurate preoperative testing methods. In this article, we provide an overview of the various laboratory testing methods that are presently available and a comprehensive literature review how various institutes and neurosurgical communities across the globe are employing them to ensure safe and effective delivery of surgical care to patients. Through this review, we highlight the guiding principles for preoperative testing, which may serve as a road map for other medical institutions to follow. In addition, we provide an Indian perspective of preoperative testing and share our experience in this regard.

Update of SEPAR guideline «Diagnosis and Treatment of Drug-Resistant Tuberculosis»

New evidence and knowledge about the clinical management of drug-resistant tuberculosis (TB) in the last 3 years, makes it necessary to update the recent guideline published by SEPAR in 2017, mainly in relation to new diagnostic methods, drug classification, and regimens of treatment recommended to treat patients with isoniazid-resistance TB, rifampicin resistance TB and multidrug-resistant TB. With respect to tuberculosis diagnosis, we recommend the use of rapid molecular assays that also help to detect mutations associated with resistance. In relation to the treatment of multidrug-resistant TB we prioritize effective all-oral shorter treatment regimens including bedaquiline, a fluoroquinolone (levofloxacin or moxifloxacin), bedaquiline and linezolid, instead of the previously recommended short-course treatment with aminoglycosides and other less effective and more toxic drugs. The design of these regimens (initial schedule and changes in the regimen if necessary) should be made in accordance with drug-resistant TB experts; the treatment should be the responsibility of personnel with experience in the treatment of TB and in TB units guaranteeing the follow-up of the treatment and the management of drugs adverse effects.

Prediagnostic loss to follow-up in an active case finding tuberculosis programme: a mixed-methods study from rural Bihar, India

OBJECTIVE

To quantify the prediagnostic loss to follow-up (PDLFU) in an active case finding tuberculosis (TB) programme and identify the barriers and enablers in undergoing diagnostic evaluation.

DESIGN

Explanatory mixed-methods design.

SETTING

A rural population of 1.02 million in the Samastipur district of Bihar, India.

PARTICIPANTS

Based on their knowledge of health status of families, community health workers or CHWs (called accredited social health activist or locally) and informal providers referred people to the programme. The field coordinators (FCs) in the programme screened the referrals for TB symptoms to identify presumptive TB cases. CHWs accompanied the presumptive TB patients to free diagnostic evaluation, and a transport allowance was given to the patients. Thereafter, CHWs initiated and supported the treatment of confirmed cases. We included 13 395 community referrals received between January and December 2018. To understand the reasons of the PDLFU, we conducted in-depth interviews with patients who were evaluated (n=3), patients who were not evaluated (n=4) and focus group discussions with the CHWs (n=2) and FCs (n=1).

OUTCOME MEASURES

Proportion and characteristics of PDLFU and association of demographic and symptom characteristics with diagnostic evaluation.

RESULTS

A total of 11 146 presumptive TB cases were identified between January and December 2018, out of which 4912 (44.1%) underwent diagnostic evaluation. In addition to the free TB services in the public sector, the key enablers were CHW accompaniment and support. The major barriers identified were misinformation and stigma, deficient family and health provider support, transport challenges and poor services in the public health system.

CONCLUSION

Finding the missing cases will require patient-centric diagnostic services and urgent reform in the health system. A community-oriented intervention focusing on stigma, misinformation and patient support will be critical to its success.