Researchers from Martin Luther University Halle-Wittenberg (MLU; Halle, Germany) have successfully detected minute quantities of SARS-CoV-2 (the virus responsible for the COVID-19 pandemic) in gargle solutions from affected patients using mass spectrometry. Although this novel method is currently under development, it may be able to supplement existing tests and be made available as a standard diagnostic tool in the future.
Currently, the most widely used diagnostic test to identify a COVID-19 infection is polymerase chain reaction (PCR). PCR is highly specific as it detects the viral genome. Alternative available tests detect antibodies against the diseases. However, as antibodies are generated in the body in response to an infection, these can only be used to detect a past infection or advanced stages of a disease. Antibody tests are regularly non-specific and may be unable to distinguish between different corona viruses that can affect humans. Therefore, testing laboratories worldwide are reaching the limits of their capabilities with regards to COVID-19 testing methods.
In response to this, Andrea Sinz (MLU) developed a novel mass spectrometry-based test to complement PCR. For their experiment, recently published in the Journal of Proteome Research, Sinz and colleagues worked with gargle solutions of three COVID-19 patients provided by the University Medicine Halle (Germany). The team developed their method to detect components of the virus proteins, not the genetic material, in these highly diluted samples.
This test takes approximately 15 minutes to complete and was reportedly successful. It is also highly specific for the virus as the corresponding proteins are only present in SARS-CoV-2. Additionally, this method could be useful in the early stages of the disease when the virus is present in the mouth and throat.
Although this novel diagnostic method is not currently available, the team are hoping it will be in upcoming months. They are also planning to work with other companies to reduce the analysis time of the test by using artificially produced virus components. This would mean the test could potentially be completely within seconds. Whilst this would be beneficial as sample preparation would no longer be as time-consuming and the measurements could be carried out by non-specialized personnel, it is yet to be determined whether this is suitable for detecting SARS-CoV-2.
Sources: Ihling C, Tänzler D, Hagemann S et al. Mass spectrometric identification of SARS-CoV-2 proteins from gargle solution samples of COVID-19 patients. J. Proteome Res. doi: 10.1021/acs.jproteome.0c00280 (2020) (Epub ahead of print); www.pressemitteilungen.pr.uni-halle.de/index.php?modus=pmanzeige&pm_id=5034