Abstract: Method and apparatus for analyzing a breath sample provide user-friendly operation and analysis. The method and apparatus provide for automatic operation and coordination of operation of and absorbent sample tube, including desorbing means, a chromatographic precolumn, a chromatographic main column, a detector, a data processor, a sample receiving tube for receiving exhaled breath sample, a sample loop for aspirating a prescribed quantity of breath sample from the sample receiving tube, a sample valve, a standard gas reservoir, and a standard gas valve. All of the foregoing are operated automatically in such that start cycles, detector cycles, fault detection cycles, standardizing, analysis, shutdown and end cycles are performed in a way which allows for straightforward and simple measurement of breath sample by a user.