Engineers at Princeton University have developed a method to test blood sugar levels by means of a laser light that is capable of reading through the epidermal layer on the palm of the hand, eliminating the need to draw blood.

"We are working hard to turn engineering solutions into useful tools for people to use in their daily lives," says senior researcher and electrical engineering professor Claire Gmachl.

"With this work we hope to improve the lives of many diabetes sufferers who depend on frequent blood glucose monitoring."

According to researchers, the method is safe and rather than causing damage to skin cells, the light waves are partially absorbed in the body's sugar molecules and the level of absorption provides the reading.

It's also accurate, says lead study author and electrical engineering graduate student Sabbir Liakat.

In order to be useful, a glucose monitor must measure blood sugar levels within 20 percent accuracy and Liakat says this method is 84 percent accurate.

"It works now but we are still trying to improve it," says Liakat, referring to the next step of paring down to portable size the bulky laboratory machine, which is likely a question of eliminating the need for its elaborate cooling system.

While glucose monitoring by means of light waves is not a new concept, the key to the Princeton method is their success at maneuvering infrared waves.

Current proposed methods like the Grove Instruments Optical Bridge employ near-infrared waves, which are not as accurate because they interact with many acids and chemicals in the skin in addition to sugar molecules.

Prick-less methods for glucose monitoring, however, are developing rapidly and could soon become a reality.

One such example is the much buzzed-about partnership of Google and Novartis to create a glucose monitoring contact lens, for research indicates tear drops are just as useful as blood drops in this field.

The Princeton study was published in the journal Biomedical Optics Express.