The Centers for Disease Control and Prevention (CDC) and the EU’s Joint Research Centre (JRC) will begin working with Siemens Healthineers to help standardize international antibody tests for COVID-19.
This will include defining the proper concentrations of antibodies in the bloodstream—mapped to the novel coronavirus’s specific proteins—that could one day be used to establish the clinical threshold for a test to correctly determine whether a person is immune to the disease.
This standardization effort could impact global serology test manufacturers in an effort to improve long-term research into patients’ antibody levels by enabling apples-to-apples comparisons, regardless of testing method, as well as to help measure the effectiveness of potential vaccines.
Currently, antibody diagnostics differ on a basic level among test manufacturers by targeting antibodies linked to different proteins found on or in the novel coronavirus. This can include the infamous spike protein as well as its subunits and receptor-binding domain—which the virus uses to enter and infect human cells—plus the internal nucleocapsid protein that encases its RNA code.
In addition, under the FDA’s rules directing companies to validate their own tests before submitting them to market or applying for an emergency authorization, each test maker typically checks their assay against their own internal standards instead of a common scientific reference.
Siemens’ research project with the CDC and the JRC aims to peg each viral protein and their associated antibodies to a specific concentration that, once achieved, would block the virus from entering cells and reproducing.
"One barrier to antibody test adoption is we don't currently have an established process to determine immunity," said Deepak Nath, president of laboratory diagnostics for Siemens Healthineers.
"Different SARS-CoV-2 antibody targets produce different levels of neutralization,” Nath added. “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.”
In early August, the FDA authorized its first tests from Siemens designed to measure more specific amounts of COVID-19 antibody activity in the blood rather than simply giving a positive or negative result. The new authorizations were granted to updated versions of previous antibody diagnostics offered by Siemens under its Atellica and ADVIA Centaur labels.
In the early stages of the pandemic, antibody tests suffered under a crisis of confidence, with many inaccurate or substandard products flooding the market amid high demand for COVID-19 testing of any kind. In April, University of Oxford researchers said many antibody tests on the market did not meet the mark necessary for mass screening efforts.
Since then, the FDA, the CDC and the National Institutes of Health have worked to independently validate antibody blood tests and have regularly published their performance results.