Work

Development of a rapid LFA test based on direct RT-LAMP for diagnosis of SARS-CoV-2

Year: 2024

Type: article

Abstract: In response to the rapid spread of the SARS-CoV-2 virus, we developed a rapid molecular approach to diagnose COVID-19 without the need for RNA extraction. The study utilized two molecular methods, RT-qPCR and colorimetric RT-LAMP, to diagnose the RdRp and ORF8 genes, respectively, in oro-nasopharyngeal swabs. Due to the high sequence diversity of ORF8 in SARS-CoV and SARS-CoV-2, it has been identified as a suitable target for virus detection. The RT-LAMP method was also carried out directly on heat-treated swab samples. The strip tests were made using gold nanoparticles and combined with the RT-LAMP for further analysis. The results showed that the isothermal amplification method had a sensitivity of 95 % (95 % C.I.: 86.08 %–98.96 %) and a specificity of 75 % (95 % C.I.: 19.41 %–99.37 %). The RT-LAMP-LFA method was able to distinguish positive and negative samples with 100 % sensitivity (95 % C.I.: 91.96–100) and 77.27 % specificity (95 % C.I.: 54.63–92.18). This method only required heating swab samples for 10 min at 65 °C before the RT-LAMP reaction. By utilizing the RT-LAMP in combination with the LFA, it is possible to diagnose SARS-CoV-2 rapidly without the need for RNA extraction. The entire process from sample collection to test interpretation takes only 75–90 min, and the results can be interpreted by untrained individuals with the naked eye. By employing the ORF8 gene as a diagnostic target and eliminating the need for RNA extraction, the direct RT-LAMP-LFA method achieves a significant breakthrough that was not previously reported. A schematic representation of the direct RT-LAMP-LFA performance for the diagnosis of SARS-CoV-2. • A newly developed rapid COVID-19 diagnostic test that doesn't require RNA extraction. • Comparison of RT-qPCR and colorimetric RT-LAMP to detect SARS-CoV-2 in swab samples. • ORF8 is a suitable target for virus detection due to its high sequence diversity. • Direct RT-LAMP-LFA achieves a rapid and user-friendly diagnostic process. • Sampling to test results takes 75–90 min, interpretable by the untraineds.

Source: Practical Laboratory Medicine

DOI: 10.1016/j.plabm.2024.e00437

Authors: Negar Sadeghi, Neda Shirazi, Moein Dehbashi, Bahareh Maleki, William C. Cho, Zohreh Hojati

Institutions: University of Isfahan, Queen Elizabeth Hospital

Language: English

Topic: SARS-CoV-2 detection and testing

Subfield: Infectious Diseases

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,140