The Wetherby-based group said data from a clinical study in Europe on 98 positive Covid-19 samples demonstrated excellent performance in identifying the SARS-CoV-2 virus across a broad range of viral loads.
The study tested 98 positive samples. Avacta’s rapid antigen test identified 96 out of 98 of these correctly as positive within a 20 minutes read time, resulting in a clinical sensitivity of 98 per cent.
Out of a total of 102 negative samples tested with the lateral flow device, the test correctly identified 101 as negative, giving a clinical specificity of 99 per cent.
This is a vast improvement on the performance of many other lateral flow tests. The Innova test had a sensitivity of 79 per cent when used by laboratory scientists, meaning that 21 per cent, or one in five, would be false negatives.
Avacta said the new data will now be combined with other performance data from ongoing studies to finalise the technical file for CE marking Avacta’s AffiDX SARS-CoV-2 antigen lateral flow test for professional use, allowing the company to begin commercial roll out in Europe in May.
The clinical evaluation of Avacta’s lateral flow test was carried out at a single site in Europe with patient samples with different viral loads.
Lateral flow rapid antigen tests provide a low cost means of identifying individuals with a high viral load that means they are more likely to infect others.
Many factors affect whether an individual will infect others or not, as well as viral load, such as the circumstances and length of exposure.
However, there is a growing consensus that a viral load of Ct<27 should be considered as infectious.
The clinical data for Avacta’s AffiDX SARS-CoV-2 antigen lateral flow test demonstrated 100 per cent sensitivity for identifying infectious individuals in this range.
Dr Alastair Smith, chief executive of Avacta Group, said: “I am delighted with the clinical data from this larger clinical study, which has robustly evaluated the AffiDX antigen test with lower viral loads of Ct>26 as well as with higher viral load samples.
“The results are very impressive and marks a major step in obtaining a CE mark for professional use.”
As part of the study, the same clinical samples were tested with two leading, commercially available lateral flow antigen tests, and the data showed that the AffiDx test had better clinical sensitivity across the range of Ct value and in particular at lower viral loads.
“We are completing the necessary assessment of the product from our manufacturing partner Global Access Diagnostics, including stability testing that will complete the technical file for CE marking, which we expect will happen in early May,” said Dr Smith.
“We are very excited by the potential of this high quality SARS-CoV-2 rapid antigen test and we are looking forward to updating the market as we commercially roll-out the AffiDX test in the coming months.”
The past year has been transformational for Avacta. Its AffiDX SARS-CoV-2 lateral flow rapid antigen test could be the most sensitive spike antigen test to date.