The present invention provides a system and method for diagnosing, screening or monitoring a disease by analyzing the breath of a test subject using a selected definitive sensor set in conjunction with a pattern recognition analyzer, wherein the pattern recognition analyzer receives output signals of the sensor set, compares them to disease-specific patterns derived from a database of response patterns of the sensor set to exhaled breath of subjects with known diseases, wherein each of the disease-specific patterns is characteristic of a particular disease, and selects a closest match between the output signals of the sensor set and the disease-specific pattern. The present invention further provides a method of diagnosing, screening or monitoring a disease based on the determination of levels of volatile organic compounds (VOCs) from a universal biomarker set, including 2-ethylhexanol, 3-methylhexane, 5-ethyl-3-methyl-octane, acetone, ethanol, ethyl acetate, ethylbenzene, isononane, isoprene, nonanal, styrene, toluene and undecane.
