Fig. 2

RT-LAMP validation results. a Electrophoresis of RT-LAMP products. RT-LAMP reaction products were analyzed on a 2% agarose gel and the DNA was stained with ethidium bromide. The typical band pattern of a RT-LAMP reaction was visible in positive samples that showed a color change from pink to yellow. Lane 1 = NTC and lanes 2–6 = positive samples. b Colorimetric readout after 30 min of RT-LAMP reaction. After the reaction, the optical densities were measured at 434 nm and 560 nm using a BioteK Synergy reader. To obtain the ΔOD (color change difference), the absorbance at 560 nm was subtracted from the one at 434 nm. The line inside the box indicates the median and the whiskers extend either to the minimum and maximum values. * Indicates difference (p > 0.001) between groups (unpaired, t-test). c Receiver Operating Characteristic (ROC) curve for SARS-CoV-2 colorimetric RT-LAMP with area under the curve of 0.92 (p < 0.0001) and 95% confidence interval (CI) 0.8924 to 0.9483. d Detection of SARS-CoV-2 through colorimetric RT-LAMP assay and comparison between colorimetric RT-LAMP results and RT-qPCR Ct values. Between the dotted lines is a conflicted area where most of the intermediate samples are found