Scientists say it may be possible to use a breath test to monitor blood sugar levels in people with diabetes.
Some diabetics have a fear of needles
US researchers have discovered people with type 1 diabetes exhale higher levels of methyl nitrates when their blood sugar levels are too high.
The team from the University of Irvine in California hope their work could replace the need for regular blood tests.
The study appears in Proceedings of the National Academy of Sciences.
The researchers used a chemical analysis technique developed to test for air pollution.
Methyl nitrate concentrations were as much as 10 times higher in children with type 1 diabetes when they were in a hyperglycaemic state, than when their blood sugar levels were normal.
Researcher Dr Pietro Galassetti said breath analysis had already shown promise as a diagnostic tool for ulcers and cystic fibrosis.
He said: "While no clinical breath test exists yet for diabetes, this study shows the possibility of non-invasive methods that can help the millions who have this chronic disease."
It is thought that methyl nitrate is a by-product of the damage caused to the body's tissues when blood sugar levels are too high.
Cathy Moulton, of the charity Diabetes UK, said: "Currently children with diabetes need to prick their fingers around four times a day to check their blood glucose levels.
"Nevertheless, this study was only conducted on 10 children and the research is still at an early stage.
"More research will be needed to prove that breath-analysis testing can be an effective way of monitoring blood glucose (sugar) levels for people with diabetes."