NEW YORK ─ Siemens Healthineers said on Tuesday that it is collaborating with the US Centers for Disease Control and Prevention and the Joint Research Centre (JRC) of the European Commission on a research project to develop a process for standardizing SARS-CoV-2 assays.
Antibody tests differ among test manufacturers and currently cannot be analytically compared because they target different SARS-CoV-2 proteins, Siemens Healthineers said in a statement. These include the spike protein, S1/S2, S1 RBD, and N protein, which are found in different parts of the SARS-CoV-2 virus.
The new process for standardizing SARS-CoV-2 assays involves anchoring each type of SARS-CoV-2 protein to a neutralization antibody titer ─ a level of antibody to block the virus from entering cells in laboratory experiments, Siemens Healthineers said. 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, the firm added.
With an international standard established and adopted by manufacturers, clinicians would be positioned to track their patients' antibody concentrations, regardless of the test method or manufacturer 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, according to Siemens Healthineers.
"One barrier to antibody test adoption is we don't currently have an established process to determine immunity," Deepak Nath, president of laboratory diagnostics at Siemens Healthineers, said in a statement. "Different SARS-CoV-2 antibody targets produce different levels of neutralization."
Nath said the R&D team at Erlangen, Germany-based Siemens Healthineers recognized that defining a level at which neutralization is conferred for different targets could lead to creating a common ground to standardize assays — not just on antibody production, but also on the 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," Nath said.
Developing a standardized process will define which concentration confers neutralization for different manufacturers’ antigen targets. Each manufacturer currently standardizes its assays independently with internal standards that are not linked to a common reference.
The results of the collaborative research project are expected to 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.