When the pandemic began, antibody testing was looked to as the kind of ace in the hole that would not only resolve the COVID-19 testing shortage fast and for good but also pave the way for society to reopen. Regrettably, those aspirations have not come to fruition. Although the lack of sensitivity has been the main stumbling block, the effectiveness of SARS-CoV-2 antibodies tests has also been hampered by lack of standardization. But a new collaboration teaming the U.S. Centers for Disease Control and Prevention (CDC), the European Commission Joint Research Centre and testing giant Siemens Healthineers has set out to fix that problem. The Diagnostic Challenge To deliver more effective treatment and achieve better outcomes, clinicians must be able to track patients’ antibody level concentrations and make comparisons regardless of test methods and manufacturers. But while they all take the approach of diagnosing COVID-19 by detecting the antibodies the body produces to combat the virus that causes it, different tests target different SARS-CoV-2 proteins. This disparity among targets, which include the spike protein, S1/S2, S1 RBD and N protein found in different regions of the virus, makes comparison between and among different tests an exercise in apples to oranges. […]
When the pandemic began, antibody testing was looked to as the kind of ace in the hole that would not only resolve the COVID-19 testing shortage fast and for good but also pave the way for society to reopen. Regrettably, those aspirations have not come to fruition. Although the lack of sensitivity has been the main stumbling block, the effectiveness of SARS-CoV-2 antibodies tests has also been hampered by lack of standardization. But a new collaboration teaming the U.S. Centers for Disease Control and Prevention (CDC), the European Commission Joint Research Centre and testing giant Siemens Healthineers has set out to fix that problem.
The Diagnostic Challenge
To deliver more effective treatment and achieve better outcomes, clinicians must be able to track patients’ antibody level concentrations and make comparisons regardless of test methods and manufacturers. But while they all take the approach of diagnosing COVID-19 by detecting the antibodies the body produces to combat the virus that causes it, different tests target different SARS-CoV-2 proteins. This disparity among targets, which include the spike protein, S1/S2, S1 RBD and N protein found in different regions of the virus, makes comparison between and among different tests an exercise in apples to oranges.
All of this makes it difficult to determine whether a patient has achieved immunity. “Different SARS-CoV-2 antibody targets produce different levels of neutralization,” noted Deepak Nath, president of laboratory diagnostics at Siemens Healthineers, in a statement.
The Standardization Initiative
The objective of the CDC, JRC and Siemens Healthineers research project is to come up with a new process for standardizing SARS-CoV-2 assays. The approach is to anchor each type of SARS-CoV-2 protein to a neutral antibody titer, i.e., a level of antibody to block the virus from entering cells in laboratory experiments. According to Siemens Healthineers, 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 payoff: Defining a level at which neutralization is conferred for different targets could pave the way to creating a common ground to standardize assays on not only antibody production but also the ability to provide immunity.
Takeaway
Currently, each manufacturer of SARS-CoV-2 antibody tests standardizes its assays independently by using internal standards that are not linked to a common reference. Creation and adoption of a standardized process defining which concentration confers neutralization for which SARS-CoV-2 protein would enable standardization by ensuring that all manufacturers targeting a particular antigen refer to common values during test development. “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.
