Apple, $AAPL, is making major progress on a no-prick blood glucose monitoring system for its smartwatch

Apple, $AAPL, is making major progress on a no-prick blood glucose monitoring system for its smartwatch, per Bloomberg.

The company believes it could bring the monitoring to market eventually.

Bloomberg reports there's still years of work ahead.

Per Bloomberg: The system uses lasers to emit specific wavelengths of light into an area below the skin where there is interstitial fluid — substances that leak out of capillaries — that can be absorbed by glucose. The light is then reflected back to the sensor in a way that indicates the concentration of glucose. An algorithm then determines a person’s blood glucose level.

Apple’s system — more than 12 years in the making — is now considered to be at a proof-of-concept stage.