The ability to quickly and cost-effectively test large numbers of people, along with vaccinations and social distancing, are the three pillars supporting the solution to this pandemic. High-volume COVID-19 diagnostic testing, however, has presented a significant worldwide challenge.
In a SARS-CoV-2 test using the Center for Disease Control-approved RT-qPCR protocol, a nasal swab sample is taken from an individual and sealed in a test tube for laboratory analysis.
The one sample per test tube paradigm simply overwhelms the testing infrastructure. Something new had to be tried: mass testing.
During mass testing, swabs from multiple people are placed in a single test tube and are processed as a single diagnostic sample. If the multi-swab test tube is negative, then no action is required.
If, on the other hand, that tube tests positive, then only those individuals need to receive the more expensive rapid testing.
Whether there is one sample per test tube or multiple samples, high-throughput automated lab equipment utilizing pipettes are typically not designed to deal with swabs.
Swabs create problems for automated pipetting systems that must be solved, including:
Rapidly rising demand for mass testing motivated the Festo LifeTech team to better understand the challenges faced in processing COVID-19 samples.
For years, Festo has produced automated platforms for LGC Biosearch Technologies’ high throughput and ultra-high throughput DNA/RNA extraction screening solutions. Working with LGC Biosearch Technologies in combination with collaborating with the mass testing community proved invaluable as the team worked toward an automated pipetting solution for COVID-19 screening.
The Festo approach to pipetting is air-over-liquid rather than positive-displacement pipette heads.
A benefit of air-over-liquid is that the control system can sense flow and pressure on the pressure and vacuum line—the line that controls the aspiration and dispensing of the target media within the pipette tip.
By sensing flow and pressure, the controller can determine whether there is a blockage at the pipette tip.
The development group wrote new code that, based on sensor information, allowed the Festo CODESYS-based control system to eject a suspect sample, reposition the pipette tip, and then re-collect the sample.
The controller was also programmed to measure displacement and ensure a clean sample and to determine viscosity.
With known viscosity, the pipetting head could be tuned for correct fluid delivery.
Monitoring the process, ascertaining conditions and collecting data creates chain-of-custody information for each sample.
Chain-of-custody is vital for assured test and response activities. Chain-of-custody data is typically accessible through laboratory information management systems (LIMS) or through a patient record system. LIMS can present data via the cloud for accessibility by authorized personnel.
Festo is continuing to invest in technology and product development activities to integrate additional functionality, performance and flexibility into future pipetting solutions.
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