Assessment of measurement accuracy of amplified DNA using a colorimetric loop-mediated isothermal amplification assay.

A colorimetric loop-mediated isothermal amplification assay detects changes in pH during amplification based on color changes at a constant temperature. Currently, various studies have focused on developing and assessing molecular point-of-care testing instruments. In this study, we evaluated amplified DNA concentrations measured using the colorimetric LAMP assay of the 1POT™ Professional device (1drop Inc, Korea). Results of the 1POT analysis of clinical samples were compared with measurements obtained from the Qubit™ 4 and NanoDrop™ 2000 devices (both from Thermo Fisher Scientific, MA, USA). These results showed a correlation of 0.98 (95% CI: 0.96-0.99) and 0.96 (95% CI: 0.92-0.98) between 1POT and the Qubit and NanoDrop. 1POT can measure amplified DNA accurately and is suitable for on-site molecular diagnostics.

Evaluation of a smartphone-operated point-of-care device using loop-mediated isothermal amplification technology for rapid and remote detection of SARS-CoV-2.

During the SARS-CoV-2 pandemic, rapid and sensitive detection of SARS-CoV-2 has been of high importance for outbreak control. Reverse transcriptase polymerase chain reaction (RT-PCR) is the current gold standard, however, the procedures require an equipped laboratory setting and personnel, which have been regularly overburdened during the pandemic. This often resulted in long waiting times for patients. In contrast, reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) is a simple, cost-efficient, and fast procedure, allowing for rapid and remote detection of SARS-CoV-2. In the current study, we performed a clinical evaluation of a new point-of-care test system based on LAMP-technology for SARS-CoV-2 detection, providing a result within 25 min (1copy™ COVID-19 MDx Kit Professional system). We tested 112 paired nasopharyngeal swabs, collected in the COVID-19 Ghent University Hospital test center, using the 1copy™ COVID-19 MDx Kit Professional system, and RT-PCR as the reference method. The test system was found to have a clinical sensitivity of 93.24% (69/74) (95% confidence interval [CI]: 84.93%-97.77%) and specificity of 97.37% (37/38) (95% CI: 86.19%-99.93%). Due to its easy smartphone operation and ready-to-use reagents, it ought to be easily applied in for instance general practices, pharmacies, nursing homes, schools, and companies. This would facilitate an efficient SARS-CoV-2 outbreak control and quarantine policy, as diagnosis can occur sooner in a near-patient setting.