Roche Elecsys IGRA TB: Automation Advantage Real, Differentiation Case Unproven Against Entrenched IGRA Rivals

Roche's Elecsys IGRA TB Test Receives CE Mark

Roche announced its Elecsys IGRA TB test received CE Mark, introducing an automated blood testing solution for identifying tuberculosis infection (TBI) in routine laboratory settings. This new solution provides rapid, high-throughput, and cost-effective testing, delivering reliable results in under 24 hours with a processing time of just 19 minutes per patient. The test achieved 91.12% positive percent agreement (PPA) and 94.57% negative percent agreement (NPA) compared to standard methods in a global multi-centre study. This advancement aims to expand global access to TBI testing, reduce reliance on manual workflows, and significantly contribute to the World Health Organization's (WHO) global TB elimination targets.

• The Elecsys IGRA TB test offers a fully automated solution for latent TB diagnosis on Roche’s widely available cobas immunoassay systems. It significantly reduces manual laboratory workloads, cuts standard processing times in half to just 19 minutes per patient, and provides rapid, high-throughput, and cost-effective testing with results available in under 24 hours.
• Evaluated in a global, multi-centre study across various incidence settings, the Elecsys IGRA TB test demonstrated high reliability. It achieved 91.12% positive percent agreement (PPA) and 94.57% negative percent agreement (NPA) against standard of care. Furthermore, it showed a relative sensitivity of 100% in bacteriologically confirmed TB patients and a specificity of 95.32% in a low-risk cohort.
• This new diagnostic solution is critical for addressing latent tuberculosis, which affects approximately a quarter of the global population and can progress to active disease. By expanding access to reliable, less invasive blood-based IGRA testing, Roche aims to support screening programs and drive significant progress toward the WHO's ambitious targets of decreasing tuberculosis deaths by 90% and new cases by 80% by 2030.

The Global Burden of Latent TB and the Need for Better Diagnostics

Tuberculosis remains one of the most significant infectious disease burdens globally. In 2023, approximately 10.8 million people fell ill with TB worldwide, with an estimated 1.25 million deaths — reinforcing its position as a leading infectious disease killer despite decades of prevention and control efforts. The WHO's End TB strategy has yielded measurable progress, reducing the global TB incidence rate by approximately 8.3% between 2015 and 2023. Longer-term trend data from the Global Burden of Disease analyses further contextualise this trajectory: between 1990 and 2021, the global age-standardised incidence rate (ASIR) declined from 173.0 to 103.0 per 100,000 population, while age-standardised mortality rates fell from 40.0 to 14.0 and DALYs from 1,650.6 to 580.3 per 100,000. Nevertheless, absolute case numbers have increased in Africa and Southeast Asia despite improvements in standardised rates, reflecting ongoing demographic and epidemiological pressures in high-burden regions.

The burden of TB is not uniform across age groups or demographic strata. In 2021, an estimated 759,300 new TB cases occurred among children aged 0–14 years (ASIR: 37.7 per 100,000), including 32,515 cases of MDR/RR-TB and 1,193 cases of XDR-TB — with female sex, younger age, low sociodemographic index, and HIV co-infection identified as disproportionate risk factors in this population. At the other end of the age spectrum, risk increases markedly with advancing age, with relative risks of 1.39 (95% CI: 1.29–1.50) in the 60–69 age group and 1.50 (95% CI: 1.38–1.63) in those aged 70 and older. Data from South Korea illustrate this shift concretely: between 2011 and 2020, the proportion of TB cases in individuals aged ≥65 years rose from 30.5% to 50.7%, and this cohort accounted for 86.8% of TB-related deaths by 2020. Males have consistently exhibited higher TB burden than females globally, though sex-based disparities have narrowed over time.

A critical but frequently underappreciated dimension of the global TB burden is latent tuberculosis infection (LTBI). Depending on the region, up to 36% of the population carries latent TB infection, though only approximately one in ten of these individuals will progress to active disease over their lifetime. This vast reservoir of latent infection represents both a diagnostic and strategic challenge — particularly in high-risk subpopulations such as people living with HIV, among whom LTBI prevalence can reach 39.3%, as observed in Mongolia. Regional heterogeneity in TB epidemiology is substantial: persistent high-burden clusters remain concentrated in sub-Saharan Africa and Southeast Asia, while countries such as South Africa and Bulgaria have recorded incidence declines of 44% and 69% respectively between 2000 and 2023 — trajectories that co-vary closely with labour market conditions and, in the case of Bulgaria, GDP per capita. These patterns underscore the interplay of biological, socioeconomic, and healthcare system determinants in shaping the global TB landscape.

Elecsys IGRA TB: Advancing Latent TB Diagnosis with Automation

The diagnosis of tuberculosis infection in clinical practice has long relied on two foundational immunological assays: the Tuberculin Skin Test (TST), the first diagnostic tool developed on the basis of acquired immune response to Mycobacterium tuberculosis, and Interferon-Gamma Release Assays (IGRAs), which remain the current standard for identifying tuberculosis infection. However, a critical limitation shared by both methods is their inability to differentiate latent from active tuberculosis. Conventional microbiological approaches — including microscopy and culture — continue to serve as the backbone of laboratory diagnosis, while molecular techniques have substantially expanded the diagnostic toolkit. Nucleic acid amplification methods, including PCR and loop-mediated isothermal amplification (LAMP), enable detection of M. tuberculosis-specific DNA and RNA with improved sensitivity and specificity. Targeted next-generation sequencing (tNGS) represents a particularly significant advance, simultaneously identifying M. tuberculosis, drug resistance mutations, and co-infecting pathogens, with demonstrated sensitivity of 83.9% in bronchoalveolar lavage fluid, 89.5% in sputum, and 100% in extrapulmonary samples, alongside 83.3% agreement with Xpert for rifampicin resistance detection and identification of 22 resistance mutations relevant to multidrug-resistant and pre-extensively drug-resistant TB.

Emerging biomarker research has identified several host-response signatures with diagnostic potential. MicroRNA-155, a recognised marker across multiple lung pathologies, demonstrated moderately high diagnostic accuracy in a meta-analysis of 122 studies, with a sensitivity of 0.87 (95% CI: 0.76–0.93) and specificity of 0.85 (95% CI: 0.77–0.91), with upregulated expression yielding superior performance — notably higher in pediatric versus adult TB populations. Blood-based transcriptomic signatures have also shown promise in pediatric cohorts, with sex-specific RNA panels identified for male patients (SLAMF8, GBP2, WARS, FCGR1C) and female patients (GBP6, CELSR3, ALDH1A1, GBP4), both achieving 85% sensitivity and 70% specificity — approaching the WHO target product profile for a triage test. Machine learning models applying Support Vector Machine and Random Forest algorithms to protein- and gene-based biomarker datasets have achieved accuracy of 97.0%, sensitivity of 99.2%, and specificity of 98.0%, further underscoring the potential of computational approaches in TB diagnostics.

For tuberculous meningitis (TBM), a cerebrospinal fluid (CSF)-based diagnostic prediction model has been developed from an analysis of 28 soluble mediators across CSF and serum samples. This model incorporates three biomarkers — interleukin-13 (cutoff: 37.26 pg/mL), vascular endothelial growth factor (cutoff: 42.92 pg/mL), and cathelicidin LL-37 (cutoff: 3,221.01 pg/mL) — yielding a specificity of 0.95, albeit with a sensitivity of 0.52, providing a disease-specific pattern relative to other meningitis etiologies. Collectively, these advances across molecular, transcriptomic, immunological, and CSF-based domains reflect the rapidly evolving landscape of TB diagnostics, where novel biomarkers and AI-assisted radiological imaging are contributing to more accurate and timely clinical identification.

Addressing Unmet Needs to Accelerate Global TB Elimination

Despite meaningful progress in tuberculosis drug development and global screening efforts, critical gaps persist in reaching the populations most vulnerable to TB infection and drug-resistant disease. Unmet needs span diagnostic access, therapeutic options, and systemic barriers — particularly for populations in conflict settings, marginalized communities, and intermediate-economy countries where resistance burden is highest.

• Vulnerable populations remain underserved: Key groups being targeted include homeless individuals (including those in jjokbang-type housing), internally displaced persons, prisoners, children, and populations living in conflict and complex emergency (CE) settings. In CE contexts, TB notification rates remain below 20% of estimated cases, and most CE countries rely on external funding to sustain drug-resistant TB (DR-TB) programmes.

• Drug-resistant TB presents an escalating therapeutic challenge: First- and second-line regimens are increasingly compromised by resistance, toxicity, and limited availability. While three new agents — bedaquiline, delamanid, and pretomanid — have been approved, they cannot serve as a definitive solution, particularly in intermediate-economy settings such as China, India, and Former Soviet Union countries, where DR-TB prevalence is highest. Barriers including intellectual property constraints continue to limit equitable access; for example, public production of bedaquiline in Brazil has been impeded by IP and monopoly pricing issues despite its 2021 introduction into the country's Unified Health System.

• Shorter-course preventive therapy (TPT) regimens are not yet universally adopted: The one-month rifapentine-plus-isoniazid regimen has been incorporated into global TPT guidelines and demonstrates strong completion rates among vulnerable populations. However, this regimen has not yet been incorporated into U.S. TPT guidelines, representing a gap between evidence and practice.

• Diagnostic access and point-of-care tools remain inadequate: Molecular diagnostics are costly and infrastructure-dependent, limiting deployment in resource-constrained and conflict-affected settings. There is an urgent need for point-of-care tools capable of differentiating TB from non-TB diagnoses in hard-to-reach populations. Mobile screening programmes — such as the Korea Disease Control and Prevention Agency's initiative, which identified 36 TB cases per 31,596 individuals screened (113.9 per 100,000) in 2023–2024 — demonstrate that symptom-based screening alone is insufficient, as approximately 75% of detected cases were classified as inactive TB and most individuals were asymptomatic or mildly symptomatic.

• The preclinical-to-clinical translation pipeline requires strengthening: Drug development timelines spanning decades underscore the need for more predictive preclinical models. Emerging approaches include advanced 3D cultures, lung organoids, humanized mouse models, and alternative host organisms (Galleria mellonella, Caenorhabditis elegans), alongside computational methods such as QSAR modelling, molecular docking, and pharmacophore modelling targeting conserved enzymes such as InhA.

• Post-tuberculosis lung disease and conflict-driven resistance represent emerging priorities: New evidence on the burden of post-TB lung disease calls for dedicated prevention, treatment, and rehabilitation pathways. Simultaneously, modern prolonged conflicts are amplifying DR-TB dynamics in affected countries and in refugee-hosting or bordering nations, threatening global elimination targets and exacerbating the broader antimicrobial resistance crisis.

Streamlining TB Screening: Roche's Automated IGRA Breakthrough

The CE Mark for Roche's Elecsys IGRA TB test marks a pivotal moment in the global fight against tuberculosis, particularly in the realm of latent tuberculosis infection (LTBI) diagnosis. For years, interferon-gamma release assays (IGRAs) have offered a more specific alternative to the tuberculin skin test (TST) for identifying M. tuberculosis infection, largely unaffected by BCG vaccination status. However, the promise of IGRAs has often been constrained by the practicalities of implementation: manual workflows, variable turnaround times, and the need for specialized laboratory infrastructure.

This new automated, high-throughput solution directly addresses these operational bottlenecks. By delivering rapid, cost-effective results in under 24 hours with minimal hands-on time, it significantly enhances the feasibility of large-scale screening programs. This is particularly critical in high-burden countries and for at-risk populations—such as contacts of active TB patients, healthcare workers, and migrants—where systematic testing and treatment of LTBI are essential to prevent progression to active disease and achieve global elimination targets. The ability to process samples efficiently and consistently could accelerate the identification of individuals who would benefit from preventive therapy, thereby reducing transmission and disease incidence.

However, while the automation and speed are significant advancements, it is crucial to acknowledge the inherent diagnostic complexities of IGRAs. Studies indicate that IGRAs, while valuable for LTBI, still face challenges in accurately differentiating active TB from latent infection. Their performance can also be suboptimal in certain vulnerable groups, including HIV-infected individuals, immunosuppressed patients, and very young or elderly populations, where indeterminate results or reduced sensitivity are more prevalent. Furthermore, discordance between IGRAs and TST, and even between different IGRA platforms, remains a documented issue, suggesting that a positive or negative result should always be interpreted within the broader clinical context and alongside other risk factors. This new technology represents a powerful tool, but it is one piece of a larger, complex diagnostic puzzle, requiring thoughtful integration into comprehensive TB control strategies.