Professors Rebecca DuBois, right, and Jacqueline Kimmey are part of a team of researchers on this project.
UCSC professors Rebecca DuBois, right, and Jacqueline Kimmey are part of a team of researchers who developed a new method to detect COVID-19 antibodies.
(Carolyn Lagattuta / UC Santa Cruz)
COVID 2022

UCSC researchers develop faster way to detect COVID-19 antibodies — without sacrificing accuracy

UC Santa Cruz researchers say they’ve developed a new method to detect COVID-19 antibodies — the signature of prior infection and persistent immunity — that’s many times faster than the current gold standard for antibody testing.

The name of the test is a mouthful: biolayer interferometry immunosorbent assay, abbreviated as BLI-ISA. Described in a paper published Thursday in Scientific Reports, the process can return results in less than 20 minutes, with a level of accuracy going well beyond currently available rapid tests, according to Rebecca DuBois, a professor of biomolecular engineering.

Researchers say the innovation could play a role in fighting the coronavirus on the UCSC campus and in the Santa Cruz community in a matter of months, and, further down the road, has potential to play a wider role in surveilling for immunity from vaccines. But because it relies on costly equipment and has yet to secure approval from the FDA, its immediate impact on the public-health battle may be limited.

Antibody tests check a person’s blood by looking for antibodies, which can indicate a past infection with the virus that causes COVID-19, according to the CDC. Antibodies themselves are proteins that help fight off infections and can provide protection against getting the disease again.

The UCSC team is on the verge of applying for FDA approval for BLI-ISA, which could be granted as soon as this spring. If the approval comes, researchers hope the method can quickly be put to use as a surveillance tool for the campus and surrounding community — perhaps in a similar fashion to the role played by UCSC’s on-campus COVID-19 testing lab.

“If we get FDA approval of this, it would be a natural fit to be part of that, to help our campus and community, and I’m hoping to help however I can,” DuBois said.

According to DuBois, the method’s key distinction from existing antibody tests is the combination of speed and precision.

Rapid antibody tests already available are as fast, and much more portable. Their result, however, is far less precise — signaling the presence of antibodies, but not their level. Whether from a prior infection or a vaccine, it’s the level of antibodies present that determines whether a person remains immune from reinfection.

A biosensor is held over an assay plate, two of the tools used in the antibody detection method.
A biosensor is held over an assay plate, two of the tools used in the antibody detection method.
(Carolyn Lagattuta / UC Santa Cruz

On the other hand, another antibody detection method — called ELISA — has comparable precision to the UCSC-developed test. That method, according to DuBois, is the current “gold standard” in the field.

But its results take at least 4 hours, she said, if not more than a day.

The slow speed of that method is what led DuBois to want to pursue the line of inquiry early on in the pandemic. “I just thought that there must be a better way to do that,” she said.

One major caveat to the new antibody testing technique is its reliance on a piece of costly equipment mostly found only in research labs. The equipment, called a biolayer interferometry instrument, has a price tag as hefty as its name — ranging into the hundreds of thousands of dollars. Previously the equipment was put to use in other research contexts, according to John Dzimianski, a UCSC post-doc researcher and the lead author of the paper.

Dzimianski said the UCSC team developed a way to retool the process to work for antibodies, an approach that had been previously considered but never demonstrated.

“We were able to take something that pretty much only been used for just basic research, and turn it into something that, you know, in a pretty short time, you know, had some sort of clinical relevance,” Dzimianski said.

A diagram of the research team's detection method, called an assay.
(UC Santa Cruz)

The detection method works by bouncing light between two surfaces, creating an interference pattern that can be analyzed.

For the UCSC team, one of those surfaces is a blood plasma sample to be tested for antibodies, while the other is a carefully prepared baseline. The shift in the wavelength of light reflecting between the samples is recorded, then analyzed with the help of a program developed by the research team.

“The more antibodies we have on the surface, the more of a wavelength shift we see,” said DuBois.

The UCSC lab is equipped to run 16 samples in a batch that takes about 18 minutes, meaning their single machine has the potential to run hundreds of samples per day.