Swiss scientists have developed a small blood testing device that resides under the skin to continuously collect results and send them to a mobile phone.

The 14mm wireless prototype, developed by scientists at Ecole Polytechnique Federale de Lausanne , can simultaneously check for up to five different substances in the blood.

Readings are then sent to a phone or laptop via Bluetooth.

The device is inserted into a patient’s interstitial tissue just beneath the skin of the abdomen, legs or arms via a needle, where it can remain for several months without needing to be removed or replaced.

"The 14mm wireless prototype, developed by scientists at Ecole Polytechnique Federale de Lausanne, can simultaneously check for up to five different substances in the blood. "

Outside the body, a battery patch provides 1/10W of power through the patient’s skin, so there is no need to operate every time the battery needs changing.

It is thought the device could be ready for patient use in four years time, and could be used to monitor chronic conditions such as cholesterol and diabetes, as well as tracking the impact of drug treatments such as chemotherapy.

Co-lead researcher Giovanni de Micheli, said; "It will allow direct and continuous monitoring based on a patient’s individual tolerance, and not on age and weight charts or weekly blood tests."

The scientists believe it could also potentially warn of symptoms before they happen, and anticipate the need for medicine.

"In a general sense, our system has enormous potential in cases where the evolution of a pathology needs to be monitored or the tolerance to a treatment tested," de Micheli added.

In animal tests, the device has been proven to reliably monitor cholesterol and glucose.

In the near future the scientists hope to test their model on intensive care patients, who require constant monitoring.

The research will be published and presented at the Design, Automation and Test in Europe (Date) electronics conference.