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. 2021 Feb 16;16(2):e0246302.
doi: 10.1371/journal.pone.0246302. eCollection 2021.

Evaluation of two automated low-cost RNA extraction protocols for SARS-CoV-2 detection

Fernando Lázaro-Perona  1 , Carlos Rodriguez-Antolín  1 , Marina Alguacil-Guillén  1 , Almudena Gutiérrez-Arroyo  1 , Jesús Mingorance  1 , Julio García-Rodriguez  1 ; SARS-CoV-2 Working Group
Affiliations

Evaluation of two automated low-cost RNA extraction protocols for SARS-CoV-2 detection

Fernando Lázaro-Perona et al. PLoS One. .

Abstract

Background: Two automatable in-house protocols for high-troughput RNA extraction from nasopharyngeal swabs for SARS-CoV-2 detection have been evaluated.

Methods: One hundred forty one SARS-CoV-2 positive samples were collected during a period of 10-days. In-house protocols were based on extraction with magnetic beads and designed to be used with either the Opentrons OT-2 (OT-2in-house) liquid handling robot or the MagMAXTM Express-96 system (MMin-house). Both protocols were tested in parallel with a commercial kit that uses the MagMAXTM system (MMkit). Nucleic acid extraction efficiencies were calculated from a SARS-CoV-2 DNA positive control.

Results: No significant differences were found between both in-house protocols and the commercial kit in their performance to detect positive samples. The MMkit was the most efficient although the MMin-house presented, in average, lower Cts than the other two. In-house protocols allowed to save between 350€ and 400€ for every 96 extracted samples compared to the commercial kit.

Conclusion: The protocols described harness the use of easily available reagents and an open-source liquid handling system and are suitable for SARS-CoV-2 detection in high throughput facilities.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Percentages of SARS-CoV-2 samples positive for the orf1ab, S and N targets with the MMkit, OT-2in-house and MMin-house methods.
The numbers over the bars indicate the percentage of positive samples for each target. Overall, 114 (81%) samples were positive with MMkit, 111 (79%) with OT-2in-house and 118 (84%) with MMin-house.
Fig 2
Fig 2. Boxplot showing the distribution of the Ct values obtained for the orf1ab, S and N targets with the MMkit, OT-2in-house and MMin-house methods.
The y-axis shows the amplification cycle (Ct). The number of data points is shown over each data set.
See this image and copyright information in PMC

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