Near-POC swab TB assays expand access despite sensitivity tradeoffs for trace signals
The review reports that new swab-based, near-point-of-care molecular tests for tuberculosis offer substantial operational and cost advantages but demonstrate reduced sensitivity, particularly for low-level 'trace' Xpert MTB/RIF Ultra results. Because trace signals frequently represent active disease, the underdiagnosis risk is highest in mild disease populations, though immediate transmission risks in these groups are comparatively lower. The authors conclude that expanded access and specimen convenience likely justify these sensitivity tradeoffs in most settings, with proposed implementation strategies to mitigate potential harms and guide empiric treatment practices.
The original study
Novel near-point-of-care TB molecular tests: navigating the repercussions of sensitivity tradeoffs.
- Authors
- Kendall EA
- Journal
- The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease
- Type
- Journal Article, Review
- PMID
- 42538628
Original abstract
New near-point-of-care, swab-based molecular tests for TB offer substantial operational advantages including improved accessibility and cost. However, early data suggest some loss of sensitivity: in particular, these tests tend to miss the lowest-positive molecular signals, such as 'trace' Xpert MTB/RIF Ultra sputum test results. Recent cohort studies suggest most trace signals represent TB disease, even if not currently confirmable by culture. However, the underdiagnosis arising from reduced sensitivity will be greatest in populations with mild disease, where immediate clinical and transmission risks may be lowest and benefits of expanded access may be greatest. Altered test characteristics may also alter empiric TB treatment practices, with variable effects on over-diagnosis. The improved access and yield offered by near-point-of-care platforms and swab specimens are likely to justify these tradeoffs, more than offsetting detrimental effects on case detection in most contexts. Implementation strategies are proposed to mitigate potential harms.