ArticleThe Lancet. Global health2025
Colorimetric RT-LAMP for SARS-CoV-2 detection from nasopharyngeal swabs or crude saliva: a multicountry diagnostic accuracy study in Africa.
Article in The Lancet. Global health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
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
2 citing papers in PubMed.
- Extraoral Detection of Biomarkers and Pathogens in Saliva: Comprehensive, Panoramic Review.Biosensors · 2026Review
- A One-Pot RT-LAMP Diagnostic Assay for SARS-CoV‑2 from Saliva Samples.ACS measurement science au · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
24 authors.
Funding
Abstract
backgroundReverse-transcription loop-mediated isothermal amplification (RT-LAMP) with colorimetric readout is a rapid, robust, and cost-effective one-step amplification assay that we previously trialled for the identification of SARS-CoV-2 in nasopharyngeal swabs in four countries. Here, we expanded our assessment of RT-LAMP for SARS-CoV-2 detection to several other African countries and evaluated its operational performance with crude saliva as a pragmatic approach for outbreak surveillance and response in resource-limited settings.
methodsWe conducted a multicountry diagnostic accuracy study of RT-LAMP for the detection of SARS-CoV-2 in different types of clinical samples. A preliminary study was conducted in Slovenia and Italy to establish the analytical performance (limit of detection) of RT-LAMP and optimise this assay before its deployment in Africa. Subsequently, we tested RT-LAMP with RNA extracted from nasopharyngeal swabs in seven countries in Africa (Angola, Burkina Faso, Côte d'Ivoire, Ethiopia, Senegal, Sudan, and Zimbabwe), and, in parallel, with crude saliva samples (ie, without RNA extraction) in an additional four countries (Cameroon, Ethiopia, Kenya, and Nigeria; paired nasopharyngeal swabs were collected at the same time). In both contexts, quantitative RT-PCR (RT-qPCR) with RNA extracted from nasopharyngeal swabs was used as the gold-standard benchmarking assay to evaluate performance. For RT-qPCR testing, each laboratory followed their own standard diagnostic procedure, whereas a standardised protocol was used for RT-LAMP. Saliva test standardisation was ensured through centralised reagent distribution. We calculated diagnostic parameters (sensitivity, specificity, and accuracy) using a 2 × 2 contingency table.
findingsThe preliminary study reported 87% sensitivity and 98% specificity for RT-LAMP. Between Sept 1, 2021, and June 30, 2022, we collected 2774 nasopharyngeal swabs and 577 crude saliva samples. For RNA extracted from nasopharyngeal swabs, the sensitivity and specificity of RT-LAMP for detection of SARS-CoV-2 (relative to the standard of diagnostics-ie, the RT-qPCR assay used in each participating laboratory) were 89% (95% CI 87-90) and 95% (93-96), respectively. Similarly, RT-LAMP tested on saliva without RNA extraction showed 80% (75-84) sensitivity and 99% (96-100) specificity (relative to the results obtained with the standard of diagnostics for RNA extracted from paired nasopharyngeal samples).
interpretationColorimetric RT-LAMP is a reliable assay for SARS-CoV-2 detection in both extracted RNA and crude saliva samples. The demonstrably acceptable performance on crude saliva samples (without RNA extraction) underscores the scalability of this method for efficient outbreak surveillance in resource-limited settings.
fundingGates Foundation.
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.