BACKGROUND: Self-testing for SARS-CoV-2 infection using lateral flow devices (LFDs) was a key component of the COVID-19 pandemic response; however, LFD performance has shown a high degree of variability. Between August 2020 and July 2023, the UK Health Security Agency (UKHSA), including predecessor organisations, undertook a three-phase SARS-CoV-2 test development and evaluation programme to independently evaluate commercially available SARS-CoV-2 LFDs, incorporating standardised laboratory assessment of test sensitivity. Here we describe results from a comparison of UKHSA laboratory assessment findings with manufacturer-reported LFD sensitivity data. METHODS: The UKHSA assessed the sensitivity of LFDs, by laboratory testing of surplus clinical samples from a secondary healthcare setting. These data were compared with manufacturer-reported clinical sensitivity data and analytical sensitivity (limit of detection [LOD; 50% tissue culture infectious dose [TCID50]/mL]) from LFD instructions for use (IFU). FINDINGS: UKHSA-determined LFD sensitivity ranged from 32 to 83%. Of 86 LFDs assessed, 73 included device sensitivity data in the manufacturers' IFU that claimed clinical sensitivity ≥85%, and 49 claimed clinical sensitivity ≥95%. No evidence of correlation was observed between manufacturer-reported test sensitivity and UKHSA determined test sensitivity, and no evidence of correlation was observed between manufacturer-reported test LOD and UKHSA-determined test sensitivity. INTERPRETATION: Laboratory evaluation found no evidence of correlation between manufacturer-reported SARS-CoV-2 LFD sensitivity data and UKHSA laboratory-determined sensitivity, supporting previous reports of discrepancies. Our findings suggest that manufacturer-reported performance data and claims for SARS-CoV-2 LFDs should be interpreted with caution and support the need for independent monitoring and testing, and standardisation of analysis methodologies. FUNDING: This study was funded by UK Department of Health and Social Care; UK Health Security Agency (formerly Public Health England and the National Health Service Test and Trace); and the University of Oxford NIHR Biomedical Research Centre.