Researchers at the University of Washington have developed GlucoScreen, a smartphone system that can accurately measure blood glucose levels. The technology consists of a test strip onto which a user places a drop of blood. Following an electrochemical reaction on the strip, the data are transmitted to the smartphone through a series of taps on the touch screen, somewhat like Morse code. Cleverly, the test strip is battery-free and instead derives power from the smartphone camera flash, and the strip can work with any smartphone with a standard touchscreen (and camera flash). So far, the technology has been shown to be as accurate as standard glucometers, and could assist with at-home testing for pre-diabetes.
Prediabetes is a puzzler, with many people being completely unaware that they have the condition. Increasing access to diagnostic technologies could help more people to become aware of their condition, and undertake lifestyle changes to avoid the development of full-blown type 2 diabetes. This latest technology aims to do just that by harnessing the power of the ubiquitous smartphone.
“In conventional screening a person applies a drop of blood to a test strip, where the blood reacts chemically with the enzymes on the strip. A glucometer is used to analyze that reaction and deliver a blood glucose reading,” said Anandghan Waghmare, a researcher involved in the study. “We took the same test strip and added inexpensive circuitry that communicates data generated by that reaction to any smartphone through simulated tapping on the screen. GlucoScreen then processes the data and displays the result right on the phone, alerting the person if they are at risk so they know to follow up with their physician.”
The system does not require a battery, and instead involves attaching a solar sensor to the smartphone camera flash. When the phone is used to obtain the blood glucose data from the test strip, the app will engage the smartphone flash, providing power to the test strip so that it can relay the data. Cleverly, the strips communicates with the phone haptically, using a series of touches on the smartphone touchscreen to relay the data. The data analysis itself takes place on the phone.
“Because we use the built-in capacitive touch screen that’s present in every smartphone, our solution can be easily adapted for widespread use. Additionally, our approach does not require low-level access to the capacitive touch data, so you don’t have to access the operating system to make GlucoScreen work,” said Jason Hoffman, another researcher involved in the project. “We’ve designed it to be ‘plug and play.’ You don’t need to root the phone — in fact, you don’t need to do anything with the phone, other than install the app. Whatever model you have, it will work off the shelf.”
See a video about the technology below.
Study in journal Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies: GlucoScreen: A Smartphone-based Readerless Glucose Test Strip for Prediabetes Screening