Scientists in Germany have started using a colourimetric analytic formulation instead of tattoo ink in order to detect health changes in the body.

For example, one sensor uses three different colours which, if injected into the dermis, change from yellow to blue when the skins pH levels rise.

So far they only have three sensors for pH, glucose and albumin (a protein that carries substances through the blood). However, these can indicate things such as diabetes or even kidney or liver failure. The scientist said they would like to use this technology as a permanent way to monitor patients at a low cost, since they simply used a smartphone camera and an app to compare the tests.

Further tests and studies will be done to determine the range of potential for this find.