Due to an increasing incidence of tuberculosis in the United States and the appearance of multiple drug resistant strains, a rapid and inexpensive test is needed to diagnose the disease. The standard PPD tuberculin test often fails in HIV infected (eg. drug using) subjects and may be ineffective in malnourished individuals or in those previously vaccinated with Mycobacterium bovis BCG. Identification by biochemical tests may require weeks and DNA techniques are very costly and usually identify a single species. High performance liquid chromatographic analysis of mycolic acids of mycobacteria provides inexpensive identification of all clinically relevant species, but has the serious disadvantage of requiring cultures grown for weeks. The proposed research will test the feasibility of using supercritical fluid chromatography (SFC) coupled with the very sensitive electron capture detector (ECD) for analysis of mycolic acids. When driven by computer software which automates analysis and performs pattern recognition comparisons to a stored database, the system should identify TB and other mycobacteria directly from sputum without culturing. The SFC-ECD system should approach the sensitivity of the DNA probes and PCR tests with the advantage of identifying all clinically relevant mycobacteria at a small fraction of the cost of the DNA techniques.