Breath tests should be more widely used to diagnose major illnesses, according to university researchers.
Technology is being developed at Swansea University to enable patients to be given the tests for diseases including diabetes, hepatitis and cirrhosis.
They claim that the method could save lives and money, and that patients could even self-diagnose at home with a kit bought from a shop before seeing their doctor.
Dr Masood Yousef, senior research assistant in the Welsh Centre for Printing and Coating at the university, said: "Breath samples are much easier to collect than blood and urine, for the patient as much as for the person collecting the sample.
"They can be collected anywhere, by people with no medical training, and there are no associated biohazard risks.
"Overall, the procedure is likely to be much more cost effective than conventional methods, potentially saving the NHS a great deal of time and money.
"Someone could even buy a test at somewhere like Boots and be diagnosed at an early stage. There is great potential."