Microfluidic Device Image
A MITOMI microfluidic device. (Credit: Sebastian Maerkl/2021 EPFL)

A reliable — and cheap — antibody test can analyze more than 1,000 samples at once and requires a small drop of blood, such as that from a finger prick.

The platform, which can analyze up to 1024 samples at once, consists of a complex network of tiny tubes carved into a plastic chip that is about the size of a USB stick. To perform the assay, the researchers feed individual blood samples and test reagents through the channels of this microfluidic chip. If antibodies against SARS-CoV-2 are present in a blood sample, a molecule generates a signal that can be detected as a fluorescent glow under a microscope.

Because the microfluidic device is very small, the amounts of blood and reagents used are a fraction of those required for standard COVID-19 antibody tests. And running hundreds of assays on a single platform means that a person can perform more assays in less time, with potential cost savings on human labor.

The researchers tested three commercially available devices to perform finger-prick blood tests, including glucose test strips used by people with diabetes to measure their sugar blood levels.