6 Breath Tests That Can Diagnose Disease

A new study shows that it may be possible to diagnose type 1 diabetes in kids even before the onset of severe illness.

Currently, about one in four kids with type 1 diabetes don’t know they have it until they start having life-threatening symptoms. However, a new study published in the Journal of Breath Research shows researchers might be able to diagnose the disease by detecting a chemical marker (acetone) in the breath that makes it smell sweet, but indicates a build-up of chemicals in the blood (ketones) that occurs when a person’s insulin levels are low. High levels of acetone in the breath can indicate high levels of ketones in the blood. The hope is that if proven effective, this breath test will help physicians make a diagnosis earlier.

Growing research suggests breath tests can be used to detect a variety of diseases, from diabetes to various cancers. Research is still early in some areas—and there are other factors beyond disease that can result in chemical markers in the blood and breath—but some medical institutions are already using the tests of a variety of diagnosis.

Type 1 Diabetes
In the new study, researchers collected compounds in the breath from 113 children and adolescents between the ages 7 and 18. They also measured the kids’ blood-sugar and ketone levels. They found a link between higher levels of acetone in the breath and ketones in the blood. “Our results have shown that it is realistically possible to use measurements of breath acetone to estimate blood ketones,” said study author Gus Hancock, a professor at Oxford in a statement. “We are working on the development of a small hand-held device that would … help to identify children with new diabetes.”

Colorectal Cancer
In a small study published in 2012 in the British Journal of Surgery, researchers from the the University Aldo Moro of Bari in Italy collected the breath of 37 patients with colorectal cancer and 41 healthy control participants. The researchers were measuring the amount of volatile organic compounds (VOCs) in the participants’ breath, with the thought being that cancer tissues and cells may release distinct chemicals. The researchers were able to identify 15 of 58 specific compounds that were correlated with colorectal cancer. Based on this, the were also able to distinguish between cancer patients and healthy patients with 75% accuracy.

Lung Cancer
In 2013, researchers from the University of Latvia used an electronic nose-like device to identify a unique chemical signature in lung cancer patients. As TIME has previously reported, there are several groups who think this process can be standardized for cancer with further research. In June, scientists at the American Society of Clinical Oncology meeting in Chicago presented a device they think has real promise.

Obesity
There are obviously a number of ways that obesity can be diagnosed without a breath test, but a 2013 study published in the Journal of Clinical Endocrinology & Metabolism found that obese people had unique markers in their breath, too. Researchers at Cedars-Sinai Medical Center studied the breath of 792 men and women trying to detect methane. Those with higher levels of methane and hydrogen gases in their breath also tended to be heavier with a BMI around 2.4 points greater than those with normal gas levels. The hope, the researchers say, is that a test could be developed that could detect a type of bacteria that may be involved in both weight and levels of gas in the breath. There may be ways to clinically curb that bacteria growth.

Lactose Intolerance
Johns Hopkins Medicine uses breath testing to help diagnose lactose intolerance. Patients drink a lactose-heavy drink and clinicians will analyzed the breath for hydrogen, which is produced when lactose isn’t digested and is fermented by bacteria.

Fructose Intolerance
Johns Hopkins also uses breath tests to assess whether an individual is allergic or intolerant to fructose, a sugar used to sweeten some beverage and found naturally in foods like onions, artichokes, and wheat. The test is similar to a breath test for lactose intolerance. Patients will drink a cup of water with dissolved fructose and over a three hour period, clinicians will test their breath. Once again, a high presence of hydrogen can indicate that the patient is not properly digesting it.