A new U.S. study shows that a simple breath test can help diagnose early lung cancer with a high accuracy rate. Researchers at the University of Louisville reported at the annual meeting of the American College of Thoracic Surgeons on the 28th that they used a mass spectrometer and a specially designed silicone microprocessor to detect the presence of carbonyl compounds in the exhaled breath of some patients suspected of having lung cancer. These patients were all suspected lung cancer patients detected by CT. Carbonyl compounds are volatile organic compounds, including aldehydes and ketones, that are produced by the body but in very low concentrations. Researchers have found that if three to four carbonyl compounds are present in higher concentrations in exhaled breath than normal, the patient has a 95 percent chance of having lung cancer. Conversely, if carbonyl compound levels are normal, then the patient has an 80 percent chance of having a benign mass. In addition, when lung cancer patients had their cancerous tissue surgically removed, the carbonyl compound levels in their exhaled breath returned to normal. Michael Busamra, an associate professor at the University of Louisville who led the study, said the breath test helps determine which patients with suspected lung cancer need immediate further testing and removal surgery, rather than sending the patient directly to a more painful biopsy. The breath test is simple and makes it easier for patients.