Comparing lateral flow testing with a rapid RT-PCR method for SARS-CoV-2 detection in the UK
Abstract
In late 2019, SARS-CoV-2 emerged in the Wuhan province of China. Rapid global spread led to the Covid-19 pandemic. Rapid and accurate detection of SARS-CoV-2 has become a vitally important tool in controlling the spread of the virus. Lateral flow devices (LFDs) offer the potential advantage of speed and on-site testing. The sensitivity of these devices compared to the gold standard RT-PCR has been questioned. We compared the performance of the Innova lateral flow kit, recommended by the UK government, with our rapid in-house RT-PCR protocol using stored positive patient samples. The LFD device was found to be 6,000-10,000 times less sensitive than RT-PCR for the detection of SARS-CoV-2. Overall, the LFD detected 46.2% of the positives detected by RT-PCR. 50% of the LFD results were observed to be weak positives, only visible after careful examination by experienced laboratory staff. At lower viral loads, such as 10,000-100,000 RNA copies/ml, the LFD detected 22.2% of positives. In addition, two strong positives (3 and 1.5 million RNA copies/ml) were not detected by the LFD. The argument for use of LFD kits, despite their lack of sensitivity, is that they detect infectious virus and hence contagious individuals. At present, there is a lack of scientific evidence supporting this claim. The LFD used in the UK fails to identify individuals with considerable viral loads and has been subject to a class I recall by the US FDA but is still approved and recommended for use by the UK government. We believe that using LFD testing for assessing SARS-CoV-2 infection risk is a strategy which has risks that outweigh any benefits.
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SciScore for 10.1101/2021.10.08.21264742: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: This study was reviewed and approved by the Micropathology Ltd Ethics Committee Review Board composed of Professor Sheila Crispin (MA, VetMB, DVA, DVOphthal, DipEVCO, FRCVS), Professor Christopher Dowson (BSc, PhD), Rt Hon Countess of Mar, Most Rev Dr Gordon Mursell (MA, Hon DD) and William NH Taylor (BTech)).
Consent: No additional consent was necessary.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
Software and Algorithms Sentences Resources Statistical analysis: Probit regression (MedCalc) was used to determine the LLoD (with 95% confidence interval) of both methods. MedCalcsuggested: (MedCalc, RRID:SCR…SciScore for 10.1101/2021.10.08.21264742: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: This study was reviewed and approved by the Micropathology Ltd Ethics Committee Review Board composed of Professor Sheila Crispin (MA, VetMB, DVA, DVOphthal, DipEVCO, FRCVS), Professor Christopher Dowson (BSc, PhD), Rt Hon Countess of Mar, Most Rev Dr Gordon Mursell (MA, Hon DD) and William NH Taylor (BTech)).
Consent: No additional consent was necessary.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
Software and Algorithms Sentences Resources Statistical analysis: Probit regression (MedCalc) was used to determine the LLoD (with 95% confidence interval) of both methods. MedCalcsuggested: (MedCalc, RRID:SCR_015044)The correlation between viral load and LFD result was calculated in Excel by first converting the LFD results into a score of 0-3 reflecting the number of replicates with a positive result. Excelsuggested: NoneResults from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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