Glucose testing on the go is about to get much easier, with the creation of a new smartphone case glucose test.

A team of engineers from the University of California San Diego has created a new smartphone case and application that allows diabetics to record and track their blood glucose readings in about 20 seconds.

The sensing system, called the GPhone, includes a slim, 3D printed case that fits over a smartphone with a permanent, reusable sensor on one corner and small, one-time use, enzyme-packed pellets that magnetically attach to the sensor.

The pellets are housed inside a 3D printed stylus that is attached to the side of the case.

“Integrating blood glucose sensing into a smartphone would eliminate the need for patients to carry a separate device,” Patrick Mercier, a professor of electrical and computer engineering at UC San Diego, said in a statement. “An added benefit is the ability to autonomously store, process and send blood glucose readings from the phone to a care provider or cloud service.”

To operate, the user first takes the stylus and dispenses a pellet onto the sensor to activate the sensor. They then drop a blood sample on top, which is measured for blood glucose concentration by the sensor.

The sensor then wirelessly transmits the data through Bluetooth to a custom-designed Android app that displays the numbers on the screen. The used pellet is then discarded and the sensor is deactivated.

The pellets contain an enzyme called glucose oxidase that reacts with glucose to generate an electrical signal that can be measured by the sensor’s electrodes.  

Previous glucose sensors contained enzymes permanently built on top of the electrodes, which eventually wore out. However, keeping the enzymes in separate pellets alleviates that problem.

“This system is versatile and can be easily modified to detect other substances for use in healthcare, environmental and defense applications,” nanoengineering professor Joseph Wang said in a statement.

The system could one day be integrated directly into a smartphone, rather than a case.

They also plan to include a function that sends phone alerts to remind users to check their blood sugar.

The study was published in Biosensors and Bioelectronics.