COVID-19 Briefing for 15th April 2020
With the COVID-19 pandemic spreading at an unprecedented rate, diagnostic services in all countries are being stretched to their limit. One way to create additional diagnostic capacity is to utilise smaller academic and non-academic laboratories. The advantage of using such facilities to undertake testing is that they tend to have closer proximity to healthcare facilities. This means they could provide a quicker turnaround time than larger more remote centralised facilities because of simpler sampling and shipping logistics. Where such laboratories could prove pivotal is in the quick testing of healthcare workers and those working in essential service industries. Crucially they could provide a means to identify those who are infected with SARS-CoV2 and need to be isolated versus those who are not infected so they can remain working.
One of the key limitations to expanding diagnostic tests to tackle COVID-19 is the lack of protocols, or validated schemes, available to laboratories to adopt. A team of scientists, clinical staff and diagnostic staff attached to Cambridge University and Addenbrooke’s Hospital have just managed to develop a SARS-CoV2 diagnostic workflow in a conventional academic Containment Level 2 (CL2) laboratory. It took them 14 days to roll-out and validate the process. Unlike onsite diagnostic laboratories where the current turnaround time is more than 48 hours, the system devised in Cambridge makes it possible to provide a result in 4 hours.
The Cambridge team have just published a blueprint of their method. Their system rests on the deactivation of SARS-CoV2 at the point at which the sample is taken. This was achieved by the team developing a special kit for swabs to be taken and transported. Detailed instructions are supplied with the kits to ensure safety of those taking the swab and for its transportation. The kits include a labelled sample tube with a secure top that contains the chemical compounds guanidine thiocyanate and b-mercaptoethanol which break down the cell membrane of the virus and deactivate it. For extra safety each tube is sprayed with ethanol and then placed in a zip lock bag which once sealed is sprayed with ethanol. This is then placed in a secure biohazard labelled for dispatch to a certified CL2 laboratory.
Careful measures have also been developed to restrict exposure to the sample when processed inside the laboratory. A number of steps are involved in processing the sample, including extracting the viral RNA from the sample and then amplifying it so that SARS-CoV2 can be detected in a Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) assay. This is a well-established method for the detection method for the detection, quantification, and typing of different microbial agents.