Will more sensitive diagnostics identify tuberculosis missed by clinicians? Evaluating Xpert MTB/RIF testing in Guatemala.

OBJECTIVE: To assess the impact of introducing Xpert as a follow-on test after smear microscopy on the total number pulmonary TB notifications. METHOD: Genexpert systems were installed in six departments across Guatemala, and Xpert was indicated as a follow-on test for people with smear-negative results. We analyzed notifications to national tuberculosis (TB) programmes (NTP) and the project's laboratory data to assess coverage of the intervention and case detection yield. Changes in quarterly TB notifications were analyzed using a simple pre/post comparison and a regression model controlling for secular notification trends. Using a mix of project and NTP data we estimated the theoretical yield of the intervention if testing coverage achieved 100%. RESULTS: Over 18,000 smear-negative individuals were eligible for Xpert testing during the intervention period. Seven thousand, one hundred and ninety-three people (39.6% of those eligible) were tested on Xpert resulting in the detection of 199 people with smear-negative, Xpert positive results (2.8% positivity rate). In the year before testing began 1098 people with smear positive and 195 people with smear negative results were notified in the six intervention departments. During the intervention, smear-positive notification remained roughly stable (1090 individuals, 0.7%), but smear-negative notifications increased by 167 individuals (85.6%) to an all-time high of 362. After controlling for secular notifications trends over an eight-quarter pre-intervention period, combined pulmonary TB notifications (both smear positive and negative) were 19% higher than trend predictions. If Xpert testing coverage approached 100% of those eligible, we estimate there would have been a+41% increase in TB notifications. CONCLUSIONS: We measured a large gain in pulmonary notifications through the introduction of Xpert testing alone. This indicates a large number of people with TB in Guatemala are seeking health care and being tested, yet are not diagnosed or treated because they lack bacteriological confirmation. Wider use of more sensitive TB diagnostics and/or improvements in the number of people clinically diagnosed with TB have the potential to significantly increase TB notifications in this setting, and potentially in other settings where a low proportion of pulmonary notifications are clinically diagnosed.

The TB REACH Initiative: Supporting TB Elimination Efforts in the Asia-Pacific.

After many years of TB 'control' and incremental progress, the TB community is talking about ending the disease, yet this will only be possible with a shift in the way we approach the TB response. While the Asia-Pacific region has the highest TB burden worldwide, it also has the opportunity to lead the quest to end TB by embracing the four areas laid out in this series: using data to target hotspots, initiating active case finding, provisioning preventive TB treatment, and employing a biosocial approach. The Stop TB Partnership's TB REACH initiative provides a platform to support partners in the development, evaluation and scale-up of new and innovative technologies and approaches to advance TB programs. We present several approaches TB REACH is taking to support its partners in the Asia-Pacific and globally to advance our collective response to end TB.

A pragmatic approach to measuring, monitoring and evaluating interventions for improved tuberculosis case detection.

The inability to detect all individuals with active tuberculosis has led to a growing interest in new approaches to improve case detection. Policy makers and program staff face important challenges measuring effectiveness of newly introduced interventions and reviewing feasibility of scaling-up successful approaches. While robust research will continue to be needed to document impact and influence policy, it may not always be feasible for all interventions and programmatic evidence is also critical to understand what can be expected in routine settings. The effects of interventions on early and improved tuberculosis detection can be documented through well-designed program evaluations. We present a pragmatic framework for evaluating and measuring the effect of improved case detection strategies using systematically collected intervention data in combination with routine tuberculosis notification data applying historical and contemporary controls. Standardized process evaluation and systematic documentation of program implementation design, cost and context will contribute to explaining observed levels of success and may help to identify conditions needed for success. Findings can then guide decisions on scale-up and replication in different target populations and settings.