Detection of SARS‑CoV‑2 Delta, Omicron and XBB variant using colorimetric reverse‑transcription loop‑mediated isothermal amplification and specific primers

Even with global vaccination efforts, COVID‑19 continues due to the emergent of new and more transmissible variants of severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) that evade immunity. Monitoring these variants is costly, often requiring whole‑genome sequencing. Therefore, there is a need for more cost‑effective and rapid alternatives for the identification of variant‑specific samples. Reverse‑transcription loop‑mediated isothermal amplification (RT‑LAMP) provides a more affordable and rapid method for detecting SARS‑CoV‑2 compared to other molecular tests. The present study designed colorimetric RT‑LAMP assays that target mutations associated with specific SARS‑CoV‑2 lineages. These assays were tested on 347 confirmed SARS‑CoV‑2 RNA samples. The results revealed promising accuracy: 92.18% for Omicron‑specific primers, followed by 80.64% for XBB and 71.57% for Delta. This assay effectively distinguishes the variants of concern, Delta, Omicron and XBB, without the use of costly equipment/facilities and does not require the specialized training of personnel. This development supports the use of RT‑LAMP as a valuable tool in healthcare systems battling COVID‑19.