The U.S. Food and Drug Administration issued an Emergency Use Authorization (EUA) for Roche’s Elecsys® Anti-SARS-CoV-2 antibody test. Designed to help assess if a patient has been exposed to the novel coronavirus as well if the patient has developed any antibodies, the Swiss multinational already started shipping the product to leading laboratories worldwide. They report a ramp-up in production to high double-digit millions per month to serve healthcare systems in countries accepting the CE mark as well as America.
What are some differentiators about this test?
A differentiator claims the company is that the test has a specificity greater than 99.8% and 100% sensitivity (14 Days post-PCR confirmation). Consequently, the company expects robust market demand by health authorities and health systems, and their reference laboratories. They report that as more is understood about immunity to SARS-CoV-2 the test may help to assess who has built up immunity to the virus.
Called the Elecsys Anti-SARS-CoV-2, it has been approved under the FDA’s EUA for qualitative detection of antibodies to SARS-CoV-2 in human serum and plasma (Heparin or EDTA). It’s intended use is as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. Emergency use of this test is limited to authorized laboratories. In the U.S., these authorized laboratories refer to those certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 US. For the FDA letter, see the link.
Regulatory Framework and Wait Times
Some countries have specific regulatory requirements, which indicate variability in timeline. Additionally other county-specific regulations, such as import requirements, may determine how and when these tests become locally available.
Currently diagnostic companies develop two types of COVID-19 test products, including 1) molecular tests, and 2) antigen and antibody tests. Molecular tests refer to reverse transcription polymerase chain reaction (RT-PCR). In this often-uncomfortable test, a throat or nasal swab from the patient is utilized to identify the presence of SARS-CoV-2 RNA. In the case of antigen-antibody tests, they include three general types including 1) rapid antibody test, 2) ELISA and 3) chemiluminescent technology.
In the case of the antigen or antibody test, the technology is used to identify or detect the presence of immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies in the blood sample. Produced by the human immune system in response to a viral infection, IgM is present at the initial phases of infection and IgG during the later phases, they are primarily visual in nature—the analyst is looking for changes to color for example.
While in the rapid antibody tests, an individual can actually see the color change in real time. In the ELISA test, a machine actually scans the color and the precision increases. This latter is more accurate than the former tests. The ELISA test appears to be favored by certain organizations such as the World Health Organization. However, it is expensive and requires sophisticated equipment, constant energy source and skilled labor to conduct the test.
For a good comparison between Molecular and Serological testing of COVID-19 patients, see Alyssa Billingsley, PharmD, RP of GoodRx.com and her breakdown of the two approaches.