No Lab Needed: Handheld Test Spots Zika and Hepatitis C in Hours

Researchers at the University of Illinois Urbana-Champaign's Grainger College of Engineering have developed a protocol that detects RNA viruses — including Zika and hepatitis C — directly in whole blood, with no laboratory purification step. It needs only a handheld fluorescence device and a portable heater, both low-power and deployable at the point of care. The work appears in Science Advances.

The approach flips standard-of-care testing on its head. Conventional protocols purify whole blood to strip out substances that interfere with molecular detection, a bottleneck that demands centrifuges and extraction instruments in centralized labs. That delay matters most in low-income countries, where early detection is critical for treating Zika and hepatitis C.

Instead of shrinking lab equipment for field use, the team borrowed from dried blood spot technology already used to detect HIV and hepatitis B. One or two finger-prick drops are dried with heat, preserving the viral RNA for amplification and fluorescence-based reading. The whole process wraps up on site within hours.

RNA proved a tougher target than the DNA the team had handled before. Enzymes in blood shred RNA into undetectable fragments, and heat during processing speeds the damage. Lead author Jongwon Lim, a former postdoctoral researcher at Illinois Grainger now at the Broad Institute of MIT and Harvard, said he tested hundreds of reagent combinations to pin down the mechanisms behind degradation and amplification failure. 'We needed to come up with a way to prevent degradation at each step of the procedure,' he said.

The study was a collaboration between the labs of bioengineering professor Rashid Bashir and electrical and computer engineering professor Brian Cunningham. The pocket-sized fluorescence reader came from Cunningham's group and was reported earlier this year in the IEEE Sensors Journal. Lim, who worked in Bashir's group, said the findings could shape detection of other RNA viruses such as Ebola and Lassa fever.

The team's earlier DNA work relied on 'biphasic reactions' that avoid the sample loss tied to conventional purification, helping hold sensitivity even at low target concentrations. Lim framed the goal as a clean break from lab mimicry: 'Our work reimagines the testing procedure from the ground up as something truly designed to be at the point of care.'