The specific aim of this SBIR phase 1 proposal is to demonstrate the feasibility of developing a sensitive chemiluminescent immunoassay for Candida mannan using monoclonal antibodies and acridinium esters. It is hoped that this assay will be simpler, safer and cheaper than conventional methods for the measurement of Candida antigen. Monoclonal antibodies to Candida mannan will be purified and characterized for their usefulness in immunoassays. They will be covalently labelled with an acridinium ester to a high specific activity and used to develop a sensitive chemiluminescent assay. The assay will be optimized and compared with current methods. The reagents used in the assay are stable. The assay should be specific because monoclonal antibodies are used and should be sensitive based on the use of a chemiluminescent label. If feasibility is demonstrated the phase II research will be to develop and produce the assay commercially. This will include instrument design and development and the conduct of clinical trials of the kit.