When WHO Director General Tedros Adhanom Ghebreyesus admonished nations to “test, test, test”, back in March of this year, testing was already recognised as a key strategy in the fight against COVID-19. In response to this, the diagnostics industry has been racing to develop new high-speed test platforms that can quickly and accurately carry out the wide-scale testing needed.
This call to arms was echoed recently by Dr David Nabarro, special envoy on Covid-19 for the World Health Organisation’s (WHO). In a recent interview he said that a test that delivers results in minutes is essential in order to live with the virus. He added: “A rapid test that is reliable, that can be used anywhere, is the absolute requirement now, it’s more important than just about anything else and will be a life changer”.
Whilst Dr Nabarro acknowledged the importance of antibody testing – which can identify whether an individual has recently been infected – he was clear that such tests were not as valuable as a virus test, for diagnosing current infection. One alternative, antigen testing, can detect current infections and like antibody tests is quick and cheap; however, it lacks the sensitivity required.
In contrast, molecular diagnostics (MDx) is considered the gold standard for infectious disease testing, with numerous advantages including, sensitivity, accuracy, multiplexing and test range.
Alongside its many advantages, there are however several drawbacks to MDx; the primary being the time to test result. Currently most testing is carried out in laboratories which means that samples must be collected and sent away for analysis and secondly the Sample Turn Around Time (STAT) in these laboratory systems is relatively long – approximately 30-60 minutes. As a result, many diagnostic companies are looking at new and innovative ways to improve the process; these include testing at Point of Care (POC), and methods of simplifying sample collection and preparation, so that in theory the test could be carried out by the general public rather than a trained ‘swabber’ or clinician. Also, given the volume of testing required, there is a significant drive to reduce the cost per test; so that routine testing can be carried out on the front line, and on a regular basis in day to day settings such as care homes, the workplace and schools.