A new health-economic analysis is providing valuable insights into the most effective and cost-efficient strategies for screening for tuberculosis (TB) infection among individuals living with HIV. The study, conducted with data from Thailand, suggests that interferon-gamma release assays (IGRAs) may offer a more economically sound approach compared to the traditional tuberculin skin test (TST), despite a higher initial cost per test.
IGRAs Demonstrate Cost-Effectiveness in Modeling
The analysis, presented at the 10th Asia Pacific Region Conference of the International Union Against Tuberculosis and Lung Disease (APRC 2026), modeled one-time TB infection screening in adults living with HIV. Researchers projected lifetime costs and health outcomes based on Thai epidemiological and cost data. The findings indicate that IGRAs, such as QuantiFERON-TB Gold Plus (QFT-Plus) by Qiagen, were associated with a roughly 41% lower modeled lifetime risk of progression to active TB compared to TST. Importantly, IGRAs also demonstrated lower projected lifetime costs per individual screened.
This cost difference isn’t simply due to a lower initial test price. The study highlights that lower downstream expenditures – those related to treatment, follow-up care, management of adverse events, diagnostic confirmation, and active TB case management – contributed significantly to the overall economic benefit of using IGRAs. These savings are particularly relevant in resource-constrained settings.
Addressing the Impact of BCG Vaccination
A key factor driving these findings is the higher false-positive rate associated with TST in populations with prior Bacillus Calmette-Guérin (BCG) vaccination. BCG is a vaccine against TB that is commonly administered in many countries, including those with high TB burdens. The study found that these false positives lead to unnecessary preventive treatment and increased utilization of healthcare resources, ultimately raising the overall cost of screening.
The Role of IGRAs and the Limitations of TST
IGRAs, including QFT-Plus, represent a significant advancement in TB infection screening. Unlike TST, IGRAs are not affected by prior BCG vaccination, making them more reliable in populations where BCG is routinely administered. QFT-Plus, specifically, requires only a single blood draw, eliminating the need for patients to return for a reading, as is required with TST. This can improve patient adherence and reduce the burden on healthcare systems.
According to Dr. Justin Chai, Director of Medical Affairs at QIAGEN, “The study provides important evidence to inform national screening guideline discussions and resource allocation in high-burden settings.” He emphasized that the results “highlight the potential value of more economically efficient screening approaches in supporting TB prevention among people living with HIV.”
Beyond Cost: Operational Considerations
While the study strongly suggests the economic benefits of IGRAs, Dr. Chai also cautioned that operational considerations remain critical. These include the need for adequate infrastructure, properly trained personnel, and efficient logistics to support IGRA testing. He also noted that further prospective cohort studies are needed to better understand the real-world feasibility of implementing IGRA-based screening programs.
The Broader Context of TB and HIV Co-infection
The importance of effective TB screening in individuals living with HIV cannot be overstated. HIV infection significantly increases the risk of developing active TB disease. Globally, TB remains a leading cause of death among people living with HIV. Early detection of latent TB infection (LTBI) – a state where a person is infected with TB bacteria but does not have active disease – allows for preventive treatment, which can dramatically reduce the risk of progression to active TB.
Current national guidelines, as highlighted in research from 2017 published in AIDS Care, recommend screening for LTBI in all HIV-infected patients. However, the optimal screening strategy – whether TST, IGRA, or a combination – remains a subject of ongoing debate and research, particularly in resource-limited settings.
Exploring Alternative Screening Strategies
Recent research is also exploring novel screening strategies. A study published in February 2026 in BMC Infectious Diseases evaluated a combination of TST and a C-TST (recombinant Mycobacterium tuberculosis fusion protein skin test). This combination achieved an area under the curve (AUC) of 0.821, suggesting a promising balance between accuracy and cost-effectiveness compared to traditional TST/IGRA approaches. The study concluded that, within the context of their research, the TST/C-TST strategy demonstrated both efficacy and economic advantages.
Costing Frameworks for Informed Decision-Making
Recognizing the complexities of TB testing, researchers have also developed costing frameworks to aid public health officials in making informed decisions. A framework published in February 2024 aims to provide guidance for local decision-making about TB infection testing, particularly given global shortages of TST and concerns about the costs of IGRA testing and laboratory capacity building. This framework is designed to be adaptable for use in different settings.
The findings from Thailand, coupled with ongoing research into alternative screening strategies and the development of robust costing frameworks, are paving the way for more effective and efficient TB prevention programs, particularly among vulnerable populations like individuals living with HIV.
