The current umbrella review summarized and systematically appraised the evidence about the effectiveness and cost-effectiveness of ACF compared to other strategies including PCF for TB detection. The summary message provided by the 12 systematic reviews and meta-analyses is that the evidence about the effectiveness and cost-effectiveness of TB ACF remains limited, context-dependent and related to various factors such as coverage, intensity, and screening tools used Regarding the effectiveness, this umbrella review shows that ACF may be effective in high-risk groups, such as people living with HIV, close contacts of TB patients, and individuals in high-prevalence areas such as urban slums. Indeed, targeted ACF interventions in these populations may lead to increased TB case detection, particularly for bacteriologically confirmed cases. However, the broader impact of ACF on national or population-level TB incidence remains unclear.

While ACF is supposed to boost case detection in targeted groups, these interventions do not appear to significantly alter the overall epidemiology of TB and there is limited evidence indicating a direct and positive effect of ACF on bacteriologically diagnosed routine TB case notifications. This suggests that while ACF is valuable for identifying and treating TB cases that might otherwise remain undiagnosed, it should be viewed as a complementary strategy rather than a standalone solution for TB control.

This is aligned with the findings of Koura et al. (2017) [23] who found that while ACF interventions led to substantial increases in TB case notifications within intervention areas, these gains rarely translated into significant changes at the national level. Only one country (Benin) demonstrated a statistically significant increase in national case notifications during the intervention period that could plausibly be attributed to ACF, largely because the intervention covered the entire country. The study underscores that while ACF can be impactful locally, its broader epidemiological effects may be limited without national scale-up—due in part to high costs, limited health system capacity, and challenges in sustaining intensive interventions over time.

This umbrella review highlights a persistent gap in the evidence: the link between TB detection through active case finding (ACF) and downstream treatment outcomes remains underexplored. While ACF can identify cases earlier sometimes among asymptomatic individuals the implications for treatment initiation, adherence, and completion are unclear. Research is especially needed to understand how acceptable treatment is for asymptomatic individuals, how often they are lost to follow-up before starting therapy, and what strategies improve retention under routine programmatic conditions. Ultimately, evaluating ACF’s true effectiveness requires tracking individuals from diagnosis through treatment completion.

The effectiveness of ACF is strongly influenced by implementation intensity and coverage. For example, Marks et al. (2019) conducted a cluster-randomized trial in Vietnam where the entire adult population of Ca Mau Province was screened annually using sputum Xpert testing, regardless of symptoms. [24]. TB prevalence declined by 44%, but this required screening 1,002 people per year for three years to prevent one prevalent case in the fourth year. While the study demonstrates that intensive ACF can reduce transmission, it also illustrates the labor and resource demands of high-coverage strategies, raising questions about scalability in other settings.

The choice of screening tools and delivery methods also impacts ACF effectiveness. Uncertainty remains over whether house-to-house visits outperform geographically closer mobile or outreach clinics in detecting microbiologically confirmed TB. Each approach has trade-offs in reach, logistics, and cost. Socioeconomic factors such as poverty, healthcare access, and infrastructure must inform which strategies are adopted. Comparative evaluations are needed to determine the most effective and sustainable screening modalities in different settings.

Despite limited data, this review supports the cost-effectiveness of ACF in high-burden and high-risk populations. Interventions using symptom screening combined with chest X-ray or molecular testing (e.g., Xpert) can achieve high diagnostic yield at reasonable cost, particularly when targeted to vulnerable groups. Gomes et al. (2022) assessed ACF across 20 countries in TB REACH Wave 5 and emphasized the importance of tailoring strategies to local epidemiology and resources. [25] Selecting cost-effective tools is key to enhancing the coverage and intensity of ACF without escalating costs. If ACF intervention may drive down transmission, the prevented secondary infections are likely to enhance the cost-effectiveness of these interventions.

This review supports a targeted, context-sensitive approach to ACF. Screening high-risk groups with tailored interventions can reduce TB incidence within these populations and contribute to overall TB control. Integrated strategies that combine active and passive case detection can broaden reach, particularly in high-prevalence settings. Supportive measures, including patient incentives and professional assistance may improve screening uptake and reduce pre-treatment loss to follow-up. Continued investment in cost-effective screening is justified by the potential for earlier detection and reduced TB burden. Comprehensive data collection, particularly on the long-term outcomes of TB screening in diverse contexts is essential to inform future interventions and policy decisions. Robust research can provide evidence-based insights that guide the development and implementation of effective TB elimination strategies.

Our umbrella review possesses significant strengths. It includes studies regardless of the language of publication, which reduces potential language bias. Also, we also covered several databases thus minimizing publication bias.

However, our umbrella review has several limitations that should be acknowledged. These limitations are multifaceted and impact the overall interpretation and applicability of the findings. Firstly, ten systematic reviews were included in the final analysis and the methodological quality of the included studies was generally moderate. Significant issues included the absence of protocol registration, the lack of comprehensive lists of excluded studies, and insufficient information regarding the sources of funding for the included studies. These factors introduce potential biases and reduce the overall reliability of the evidence.

Another notable limitation is the methodological heterogeneity across the included systematic reviews and meta-analyses. The diversity in study designs, populations, and outcome measures complicates direct comparisons and synthesis of the findings. This heterogeneity hampers the ability to draw definitive conclusions about the relative effectiveness and cost-effectiveness of ACF compared to PCF and various ACF strategies.

But perhaps the most significant limitation of this umbrella review reflects a broader limitation in the field itself: the included systematic reviews and the primary studies they synthesize have largely focused on intermediate outcomes such as case detection and diagnostic yield, rather than on more consequential endpoints like reductions in TB prevalence or transmission within the screened populations. These limitations highlight the need for more robust, context-specific research to fill the existing evidence gaps and provide clearer insights into the effectiveness and cost-effectiveness of ACF in different settings.