COVID-19 detected via highly diluted gargle samples

Pharmacologists have succeeded in detecting minute amounts of the coronavirus SARS-CoV-2 using mass spectrometry in solutions with which COVID-19 patients gargled. The new method could serve as a supplement to previously used tests.

SARS-CoV-2 detected through mass spectrometry

Pharmacologists at the Martin Luther University Halle-Wittenberg (MLU) have succeeded in detecting minute amounts of the coronavirus SARS-CoV-2 using mass spectrometry. For their investigation, they used solutions with which COVID-19 sufferers had gargled. In the future, the new method could serve as a supplement to previously used tests. It is now being further improved to become a standard diagnostic tool. Initial results have been published in the Journal of Proteome Research.

There is currently one reliable test method in particular for finding out with certainty whether someone has acute COVID-19 disease: the polymerase chain reaction, or PCR for short. It detects the viral genome and is therefore very specific. Other tests, on the other hand, usually detect antibodies against the disease, which the body only forms during the course of the infection, so that they can only be used to detect past or advanced stages of the disease. Furthermore, antibody tests are often non-specific and sometimes cannot distinguish between the different coronaviruses that can occur in humans. Plus, test laboratories worldwide are reaching their capacity limits for current test formats.

Prof. Dr. Andrea Sinz, a mass spectrometry expert at the Institute of Pharmacy at MLU, had the idea of developing a new mass spectrometry-based test to complement PCR. Mass spectrometry allows the precise identification of molecules based on their mass and charge. Dr. Sinz and her research team developed a method to search for components of SARS-CoV-2 viruses. "We directly measure the peptides originating from the virus, not the genetic material," explained Dr. Sinz.

The test can be performed in 15 minutes

The Halle University Hospital provided gargle solutions from three COVID-19 patients for the experiments. Dr. Sinz's research group developed a method to identify virus components in highly diluted samples. "Although we received only a small amount of gargle solution, we were able to find components of the viral proteins," says Dr. Christian Ihling, who carried out the tests. "This was quite surprising, I didn't expect it to really work myself," adds Dr. Sinz. The test is highly specific for the virus because the corresponding proteins only occur in SARS-CoV-2. In addition, the test can be used to test well in the early stages of the disease, when many viruses are found in the mouth and throat.

Currently, the test can be performed in about 15 minutes, said Dr. Sinz. The research group is now trying to further reduce the analysis times. For this purpose, they are currently using artificially produced virus components. Dr. Sinz is also looking for further research cooperation opportunities. "Together with a company from Hesse (Germany), we are planning to use another mass spectrometric method that would enable measurements to be carried out within seconds," said the pharmacist. This method would then be compared to what is known as "biotyping", which is already established in hospitals for the diagnosis of bacterial or fungal infections. However, it remains to be seen whether this approach is suitable for the detection of SARS-CoV-2. Sample preparation would then not be time-consuming and the measurements could also be carried out by non-specialized personnel.

The new diagnostic method using mass spectrometers will not be available immediately. Dr. Sinz hopes that it will be ready for use in a few months. Dr. Sinz is also a founding member of the COVID-19 Mass Spectrometry Coalition, a research association that aims to use mass spectrometry to better understand the disease.