ArticleResearch square2026
Xpert Ultra on nasopharyngeal swabs detects one-third of pulmonary tuberculosis: a nested case-control study in South African primary care.
Article in Research square, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
10 authors.
Funding
Abstract
Background: Sputum-free alternatives for tuberculosis (TB) diagnosis are a public health priority. Nasopharyngeal swabs (NPSs), a specimen routinely used for viral testing especially at-scale in outbreak investigations, may have promise but has not been evaluated in people investigated for TB. Methods: We evaluated Xpert MTB/RIF Ultra (Ultra; Cepheid, Sunnyvale, California, USA) on stored NPSs (NPSU) from adults with presumptive TB consecutively presenting to primary care in Cape Town, South Africa. Using a nested case-control design, all participants with TB had a NPS tested (n = 148) and people without TB (n = 117) were randomly selected matched by HIV status. We used a microbiological (MRS) and extended microbiological reference standards (eMRS). A subset of convenience-sampled casescontrols also received flocked tongue swab Ultra (TSU) (n = 57 cases, n = 66 controls). Results: Twenty-one (8%) of NPSUs were unsuccessful (all errors). NPSU sensitivity was 35% (95% CI 27, 43), specificity 88% (80, 93). Sensitivity was lower in HIV-positive participants [24% (14, 36) vs. 44% (32, 56)]. TSU had higher sensitivity [67% (53, 79) vs. 28% (17, 42) in the head-to-head comparison, detecting 22 additional cases] than NPSU. Specificity was comparable. Conclusion: NPSU sensitivity (35%) was lower than TSU and below the WHO target of 80% for non-sputum confirmatory tests; specificity (88%) was also below the 98% target. NPSs may have utility if already collected in mass testing campaigns for other diseases but unless performance can be optimized (e.g., by using purpose-built swab platforms) do not appear useful for TB diagnosis.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.