(AGENPARL) – UNITED KINGDOM, gio 26 novembre 2020
DnaNudge is an RT-PCR Assay “lab on a chip” cartridge design for Point of Care use. System designed as a portable reader and a disposable Cartridge with a sample to result time of approx. 90 minutes. Downside can only test a single sample at a time. Use of several devices per clinical area and appropriate prioritisation of samples is therefore advised. Time from sample to result 90 minutes.
Nasopharyngeal swab or Sputum
Clinical Sensitivity 94 – 97%
Clinical Specificity 100%
A recent evaluation study comparing DnaNudge to a standard RT-PCR in 386 paired samples found 94% sensitivity, for further information, see Gibani et al.
Initial evaluation Imperial NHS Trust London, (Various sites) Oxford University Hospitals NHS Trust (John Radcliffe Hospital) , also see recent evaluation study Gibani et al., comparing DnaNudge to a standard RT-PCR in 386 paired samples which found 94% sensitivity.
Both. The Initial evaluation included:
- Self-referred symptomatic Health care workers
- AE attendance of potential COVID-19 cases
- Asymptomatic Hospital In-Patient admissions
Dependent on prevalence rates. The positive and negative predictive values are highly dependent on prevalence rates. Positive test results are more likely to represent false positive results during periods of little/no SARS-CoV-2 activity when disease prevalence is low. False negative test results are more likely when prevalence of disease caused by SARS-CoV-2 is high.
The platform comprises two components: the DNACartridge and a processing unit (NudgeBox) (fi). The DNACartridge (25?×?78?×?85 mm; 40 g) is a disposable, sealed, and integrated lab-on-chip device that enables sample-to-result PCR.
The DNACartridge consists of two main parts: an amplification unit and a sample preparation unit. A nasopharyngeal or oropharyngeal swab is immediately inserted directly into the swab chamber of the sample preparation unit at the time of collection. The swab is broken, leaving the swab tip and the sample within the chamber, which is then sealed. Cartridges are placed in the Nudgebox processing unit (28?×?15·5?×?13·5 cm; 5 kg), which provides the pneumatic, thermal, imaging, and mechanics required to run a real-time RT-PCR reaction outside a laboratory setting.
The sample preparation unit consists of a rotating mixing unit and circumferentially distanced chambers containing buffers to extract and purify RNA from the swab sample, as well as a lyophilised PCR master-mix to mix with the extracted RNA. The sample preparation unit mixing chamber fits on top of a motor-driven spigot in the NudgeBox, which rotates the mixing unit through each stage of sample processing before filling the wells of the amplification unit, inside which the PCR reaction takes place.
Exposed surfaces of the instruments are cleaned regularly between operators with 10% bleach, followed by an isopropyl alcohol wipe to remove any residual bleach. Following the test, the single-use cartridge is disposed of following standard laboratory disposal procedures.
Each Cartridge tests for 7 targets of SARS-CoV-2 genome:
CDC-N1 10 Replicates
CDC-N2 10 Replicates
CDC-N3 10 Replicates
Charite Berlin-E 10 Replicates
Institute Pasteur –RdRP-IP2 9 Replicates
Institute Pasteur –RdRP-IP4 9 Replicates
RNAseP Control 6 Replicates