It’s not that difficult to see or even hear when a person is sick, but did you know that some doctors can smell when you have diseases like diabetes?

For ages a strong sense of smell has been an advantage in medicine. The ancient Greeks tried to identify diseases through breath and there are even hearsay stories about dogs that can identify diseases based on the smell of a person’s urine.

According to the American Diabetes Association, diabetes can often be identified through sensory symptoms like feeling thirsty, looking tired or experiencing a tingling sensation in the hands/feet. But doctors can even distinguish the sugar sickness through its unique smell.

What does diabetes smell like?

A sweet, fruity odour in the breath signals diabetes. An article in the Journal of Medical and Biological Engineering explains that this fruity smell is due to the elevated levels of acetone. Other diseases that are easy to sniff out include advanced liver disease, which has a fishy smell and failing kidneys, which is associated with urine-like smell.

However, some illnesses are more difficult to diagnose because the concentration of substances that enable disease detection is very small. Israeli chemical engineer, Dr Hossam Haick, has taken one step closer to sniffing out more complex diseases by turning to nanotechnology to develop the “electronic nose”.

How it all started

While Haick was busy with his doctorate at the Israel Institute of Technology, a friend of his was diagnosed with leukaemia. Haick says it was very painful for him and although his friend recovered, he went through a very difficult recovery process. “That was the first time I began to think about diagnosing cancer by means of oxygenating substances,” Haick says in an interview with Guy Grimland.

Today Haick spends most of his time working on an “electronic nose” to detect several types of diseases in their early stages.

How ‘the nose’ works

An article in the Scientific American journal explains how Haick’s electronic nose uses breath tests and a system of electrodes to detect diabetes and other diseases like cancer, Parkinson’s disease and pulmonary hypertensions.

1. When a patient breathes into the electronic nose, the molecules in their breath bind to the electrodes.

2. Each electrode is covered by one of 20 films which is each sensitive to a different component in the breath.

3. If the breath contains any component associated with a specific disease, the film would react and transmit the data to a computer chip.

4. The chip analyses the components through a network of algorithms and identifies them based on templates.

5. If they match 1 of the 17 diseases that the chip recognises, it presents the diagnosis.