Blood test detects past infections with new coronavirus

UW Medicine Virology
Greg Pepper, lab manager in the UW Medicine clinical virology lab, performs the Abbott antibody test for a past coronavirus infection on a blood sample

A new clinical blood test will start being conducted at the UW Medicine Virology Lab, beginning next week, to check people for past infection with SARS-CoV-2.

The test looks for the presence of an antibody, called IGg, which people produce in fending off the pandemic coronavirus. The antibody first appears several days or longer after a person contracts the virus, even in those who never had symptoms or had just mild to moderate respiratory illness.

"There are people who say, for example, 'I was pretty sick back in February. Could I have had COVID-19? back then?' said Dr. Keith Jerome, professor of laboratory medicine at the UW School of Medicine. Nasal swabbing screens for a present infection, but can't indicate whether someone had the infection in the past and recovered. The antibody blood test can. The test is done on a venous blood draw. While it is not a rapid finger-prick test, once the specimen arrives at lab it can be analyzed promptly.

The UW Medicine Virology lab is receiving shipments of this Abbott laboratory test for clinical use. Earlier, UW Medicine researchers helped evaluate the test. They compared blood samples from confirmed cases with samples taken for other reasons before the new coronavirus emerged.

The tests are expected to improve medical understanding of the virus, including how long antibodies stay in the body and if they provide immunity. This knowledge could support the development of treatments and vaccines. The appearance of certain antibodies in the blood could become one of the markers that an experimental vaccine is conferring resistance to the infection.

Earlier, the UW Medicine Virology lab helped Abbott evaluate the performance of its viral assays and how best to use them. The widespread availability of tests for immunity to the pandemic coronavirus could be vital to the re-opening of businesses and schools and return of workers. Compiling results can also reveal how prevalent the pandemic has been in certain localities or popular.

UW Medicine virologists received early access to the assay, and check it in a large number of blood samples stored for other reasons. They found the assay was highly sensitive for antibodies to SARS-Cov-2, and also highly specific. It could spot a past history of infection with this new coronavirus, and not confuse it with other viruses, including other respiratory coronaviruses.

Among the researchers who worked on evaluating the Abbott antibody test was Dr. Alex Greninger, assistant professor of laboratory medicine in its virology division. The offering of this new test is another major achievement during this pandemic for UW Medicine Virology. Soon after cases requiring hospitalization in Washington state appeared, Greninger was instrumental in obtaining FDA approval for his team's laboratory-based test of nasal swabs to diagnose active cases of COVID-19 at UW Medicine labs, instead of waiting for results from distant labs.

Patients will be able to obtain the new antibody blood test through an order from their healthcare provider. Nurses in employee health centers eventually may be able to request testing for members of their workforce, and the test may eventually become part available through certain public health programs.

Jerome described the advent of high-performance antibody tests as another positive turning point in the pandemic. This advance is, he said, is similar to the milestones reached in new options for testing for the presence of the disease and successes in flattening the curve of new cases in some places through public health measures.

The hope is now that the next milestones on the path to stemming the pandemic will be reached: greater access to testing, effective treatments, preventatives and vaccines.

"We are looking forward to the days when people start going back to work and enjoying their social lives again," he said.

Please see the Abbott news release describing their diagnostic antibody test.

Watch the YouTube archived video of the April 17 press conference with Jerome and Greninger.

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