Researchers at Northwestern University  that reads used to measure ion and molecule concentrations. The sensors are made out of fluorescent polymer beads that take only seconds to make. The sensor is then "tattooed" to an area of a patient's skin. With this in mind, a patient would be injected in the tattoo area with the nanomolecules--they would then attach themselves to glucose in the patient and start releasing ions. 

Using a special reading case strapped to the iPhone, the patient's arm is simply scanned by the phone's camera, and it gives a blood glucose measurement. The higher the glucose level, the more fluorescent the tattoo will appear on the skin--remember the sensors on the tattoo are fluorescent so will be visible under certain light. 

The iPhone case contains a 9-volt battery, a filter that fits over the phone's camera, and three different colored LEDs that produce the different levels of fluorescent light. The LEDs and filter react to outside light and can fade the colors, so the gadget is placed onto the patient's skin at first to produce a more accurate reading.  

The team hope in the future to create an app to record the levels easier for consumers, as well as extend the new technology to other conditions needing blood tests for readings, as well as other substances for measuring purposes, such as oxygen levels to look for respiration problems. 

So, there may not be an app for that yet, but your iPhone certainly can be used for just about every aspect of your life. Tell me when it learns how to bake cookies like , okay?