- Product made by Shenzen-based biotech company BGI Group gets top marks in sensitivity test for gene that affects how the novel coronavirus replicates
- Increased sensitivity helps to detect infection in people with only mild or no symptoms, head of research team says
In laboratory tests, the commercially available reverse transcriptase-polymerase chain reaction (RT-PCR) kit made by Shenzen-based biotech company BGI Group achieved the lowest limit of detection (LOD) score, suggesting it was more sensitive to the presence of the coronavirus than comparable products.
In scientific testing, an LOD is the lowest quantity of a substance that can be distinguished from a total absence of that substance with almost 100 per cent accuracy. In this case, the researchers were looking at test kits that identify the ORF1ab gene, which affects how the coronavirus replicates and how virulent it is.
The research was carried out by a team from the National Institute for Public Health and the Environment, an independent agency under the Dutch health ministry, led by virologist Dr Adam Meijer.
The results were published last month on bioRxiv, a preprint website for scientific studies that have not been peer-reviewed.
In the test, the Chinese kit returned an LOD of 4.3 copies (of the gene) per millilitre, followed by the South Korean product with 4.8. The German and Spanish kits both scored 18, while the British kit fared worst of all with 23.
When asked about the significance of the results, Meijer told the South China Morning Post that all of the products were of a suitable quality for mass testing for Covid-19, but the ones with a greater degree of sensitivity would be preferable in certain situations.
“When you expect low viral loads because of the nature of the patients being tested – such as health care workers with mild or no symptoms, or patients during later stages of the infection – it is best to choose a test that has the highest sensitivity,” he said.