In a few months, a new mass spectrometry-based method could join PCR as a key tool in the COVID-19 diagnostic testing lineup.
Developed by pharmacists at Martin Luther University Halle-Wittenberg, the test uses gargle samples from patients rather than throat or nasal swabs. Instead of detecting the genetic material of the SARS-CoV-2 virus like the PCR tests currently used, the mass spec test detects proteins in the COVID-19-causing virus, according to a press release from the university.
According to early results on the method published in the Journal of Proteome Research, the test involves “an acetone precipitation of proteins, followed by a tryptic digestion and a targeted mass spectrometric analysis of SARS-CoV-2 proteins,” allowing researchers to identify SARS-CoV-2 peptides in “highly diluted” gargle solution samples.
The method still has a ways to go and has only been tested using samples from three patients already confirmed to have COVID-19 by three PCR tests, the journal article states. However, the mass spec test was able to detect small amounts of the virus in samples and researchers say it only takes 15 minutes to perform, though they are hoping to reduce that time further.
"Although we received only a small amount of gargle solution, we were able to detect components of viral proteins," says Dr. Christian Ihling in a press release.
Mass spectrometry expert Andrea Sinz, who came up with the idea for the mass spec-based test and is also a professor at the university, adds in the press release that they are still fine-tuning the method and are partnering with a company from Hesse “to use another mass spectrometric method that would enable us to perform measurements within seconds." Sinz also helped found the COVID-19 Mass Spectrometry Coalition which is dedicated to using mass spectrometry to fight the disease.
The researchers state in their journal article that, going forward, they are planning to test their method in other types of samples, including bronchoalveolar lavage.
“The future goal is to provide robust, sensitive, and reliable MS-based methods as a routine diagnostic of COVID-19 patients that complement PCR-based methods,” they write.