Siemens Healthineers announced today that it will collaborate with the U.S. Centers for Disease Control and Prevention (CDC) and the Joint Research Centre (JRC) of the European Commission to develop a process for standardizing SARS-CoV-2 assays. The intent is to develop a method that will provide information about the actual concentrations of antibodies, as opposed to the current, semi-quantitative assays that report antibody activity to the virus.
While test developers have stepped up efforts to launch antibody tests to address the pandemic, the tests differ greatly between manufacturers and target a range of SARS-CoV-2 proteins, which prevents them from being analytically compares. Proteins targeted by current antibody tests include the spike protein, S1/S2, S1 RBD, and N protein, which are found in different parts of the SARS-CoV-2 virus.
Antibody test results have evolved since the early days of the pandemics from qualitative positive/negative results to ones that can provide numerical measurements that gauge the level of IgG antibodies in a patient’s blood sample. But, because comparing test results across manufacturers has not been possible, establishing immunity associated with these tests has been challenging.
“One barrier to antibody test adoption is we don’t currently have an established process to determine immunity,” said Deepak Nath, Ph.D., president of Laboratory Diagnostics, Siemens Healthineers in a press release. “Different SARS-CoV-2 antibody targets produce different levels of neutralization. Our R&D team recognized that if you could define a level at which neutralization is conferred for different targets, you could create a common ground to standardize assays—not just on antibody production, but their ability to provide immunity. Our collaboration with the CDC and JRC will develop the framework that all antibody test manufacturers would be expected to adopt moving forward for greater benefit to patient care as the pandemic evolves.”
Siemens Healthineers’ collaboration with the CDC and the JRC will develop a novel process for standardizing SARS-CoV-2 assays by anchoring each protein to a neutralization antibody titer—a level of antibody present to block virus from entering cells in laboratory experiments. The thresholds displayed in the standardized unit of measure for IgG—arising either from natural infection or vaccination—may likely contribute to a standardized interpretation of immunity through test results.
Developing a standardized process will define which concentrations of antigen targets confer immunity. Test developers currently standardize their own assays independently with internal standards that are not linked to a common reference. The collaborative will support the JRC’s production of a reference material, with assigned concentrations of antibody specific to each viral protein that will allow manufacturers to refer to standardized values.
Establishing such an international standard would allow healthcare providers to to track patients’ antibody concentrations, regardless of the test used. This capability is expected to improve patient care by enabling long-term antibody level comparison—clinical information that is important for verifying natural immunity acquired by patient’s infection with the virus, as well as for determining the effectiveness of vaccines.