Fig. 2 | Scientific Reports

Fig. 2

From: A colorimetric reverse-transcription loop-mediated isothermal amplification method targeting the L452R mutation to detect the Delta variant of SARS-CoV-2

Fig. 2

The performance of the colorimetric RT-LAMP assay. (a) Optimal incubation time at 60 °C used serial dilutions of the plasmid standard including 50, 500, 5000, 50,000, and 500,000 copies per reaction for 40, 60, and 75-min time points. The results provide excellent visual detection within a 75-min incubation period for RT-LAMP. (b) The analytical sensitivity assay using the L452R-specific plasmid standard that was diluted in a series had a range of 0–1000 copies per reaction. The LoD was demonstrated to be 100 and 50 copies per reaction, with a positive rate of 100% and 90%, respectively. These results were used to calculate the LoD95 to improve the analytical sensitivity, which was determined to be 57.00 copies per reaction using Probit regression analysis using Analyse-it software. (c) The analytical specificity assay used a plasmid standard and a sample group of genomic RNA samples, including human coronavirus (HCoV-229E), IAV subtype H3N2, IBV, Victoria lineage, and RSV. Furthermore, there are additional viruses, including PEDV, HAV, EV71, HSV, DENV1-4, ZIKV, CHIKV, and JEV. PC: Positive control (L452R-specific plasmid standard); NC: Negative control (DNase/RNase-Free Distilled Water).

Back to article page