Siemens Healthineers AG expects to have a total antibody test available in late May 2020 to identify individuals exposed to the SARS-CoV-2 virus that causes COVID-19. The rapid diagnostic test detects IgM as well as IgG and other antibodies in the blood. The wider range of antibodies tested enables confirmation of infection two to seven days after exposure, substantially earlier than IgG only assays, Deepak Nath, president of the Erlangen, Germany-based company's laboratory diagnostics division, told BioWorld.

IgG is typically generated four to 10 days after a coronavirus infection and builds up slowly over time. IgM can identify any patient who has mounted an immune response to the virus, even if they were asymptomatic, said Nath.

The earlier time frame means the test can also be used to identify active infections. “The test is able to detect antibodies very close to initial onset of infection,” said Nath. “It can be as short as two days after exposure.”

The serological test has demonstrated sensitivity and specificity of more than 99%. That makes it more accurate than the 95% sensitivity threshold established by the U.S. FDA in a recent update to its guidance for antibody tests.

In an attempt to expedite availability of the tests to help identify people who have had the disease and could potentially have immunity, the FDA had not initially established any required level of accuracy. Dozens of tests have been developed and released that have up to a 15% risk of producing a false negative result.

“While the FDA standard has been evolving, we have relied on how we develop assays in general and applied standards that we would feel comfortable with producing and submitting to the FDA,” Nath noted. “What the world needs now is accurate, high quality tests produced in processes that have stood the test of time.”

The focus on accuracy led to a test that is distinctive in several ways, Nath pointed out. “First, it allows earlier detection, closer to the date of the virus infection. Second, this test is more sensitive and potentially more accurate in detecting both those in active infection phase and those who had prior infection whether or not they had symptoms. Third, the design of the assay focuses on the S1 receptor on the spike protein of the virus, which is the target of many vaccines in development.”

Siemens Healthineers has been in discussion with the FDA for Emergency Use Authorization for the assay “for a couple of weeks,” Nath said. “While our initial focus is to get clearance under the EUA pathway, we do intend to file under the 510(k) pathway as well.”

Broad access

The tests will be available on the Siemens Healthineer’s Atellica Solution immunoassay analyzer, which can process up to 440 tests per hour and produce results in less than 15 minutes, according to the company. It can also be run on the ADVIA Centaur XP and XPT systems, which can analyze up to 240 tests per hour, with results in 18 minutes.

Currently, about 11,000 Atellica and Centaur analyzers are installed worldwide. About 30% of the systems are in U.S. laboratories and hospitals.

Siemens Healthineer is also developing a comparable test that can run on its Dimension Vista and Dimension EXL systems, which is expected to be available in mid-June. Of the approximately 7,000 Dimension systems installed worldwide, roughly half are in the U.S., Nath said.

Expansion of production capability at the company’s Walpole, Mass. Manufacturing facility will enable Siemens Healthineers to produce more than 25 million total antibody tests per month starting in June.

COVID-19 testing portfolio

The company is also developing an IgG only test to provide flexibility for testing needs as the pandemic evolves.

“We believe that fundamentally we need to have multiple tests to piece together what’s happening with the patient, beginning with PCR to other tests of immune response. IgG has the greatest potential to determine the effectiveness of a vaccine once one is on the market as it targets the S1 receptor part of the spike protein of the coronavirus that is under investigation by several drug manufacturers for a vaccine,” Nath explained.

The new assays will build on Siemens Healthineers’ portfolio of tests for COVID-19. Other tests available include the molecular Fast Track Diagnostics SARS-CoV-2 test kit used to diagnose the infection, which is available for research use in Europe and pending EUA approval by the FDA and Emergency Use Assessment and Listing from WHO.

“With this molecular diagnostic assay, we want to make a contribution to fight the current COVID-19 global pandemic by delivering fast and accurate SARS-CoV-2 testing,” said Sebastian Kronmueller, head of molecular diagnostics at Siemens Healthineers. “The Siemens Healthineers assay is designed to help researchers positively identify the virus in less than three hours so that healthcare professionals can proceed as quickly as possible with the necessary next steps on their patients’ triage paths.”

The company’s critical care testing solution, Rapidpoint 500e Blood Gas Analyzer received clearance from the FDA on March 31, 2020. It analyzes blood gas, electrolytes, metabolites, co-oximetry, and neonatal bilirubin results, which are used to evaluate critically ill patients.

“The Rapidpoint 500e Blood Gas Analyzer has become a trusted instrument in Europe’s endeavor to combat COVID-19 and to help address an unprecedented demand for blood gas testing in affected respiratory patients,” said Christoph Pedain, head of point of care diagnostics of Siemens Healthineers.

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