ORONO – Researchers at the University of Maine are working to develop a “breath-print” so doctors can use a patient’s breath to diagnose illnesses.

During physical exams, doctors regularly ask patients to take a deep breath and exhale. But this project aims at allowing doctors to detect everything from a high cholesterol level to dangerous exposure to a toxic substance.

It sounds easy enough – have the patient blow into a machine, then analyze the breath for compounds that hint at the presence of illness.

But scientists working on such technology haven’t found a way to make it simple and affordable for widespread use. That’s where the University of Maine comes in.

There are several hundred compounds present in very low levels in exhaled human breath, including everything from nitrogen and carbon dioxide to volatile organic compounds. Their levels may rise as the body reacts to illness or environmental exposures.

“With the common cold, sometimes before you even see the symptoms your body starts [reacting] and so you can actually see the chemicals,” said Touradj Solouki, an assistant professor in the chemistry department at the university.

People have been trying for hundreds of years to read the chemical message in a puff of human breath. There are some instruments available to analyze single compounds, such as nitric oxide, but there is nothing sensitive enough to make breath analysis as useful as a blood test in sniffing out disease.

UMaine scientists are trying to document the chemical signatures, figure out which are most important for detecting illnesses, and ultimately develop microsensors that would become part of the doctor’s medical bag.