The OpTest system has been conceived of and demonstrated in response to pressing diagnostic needs. It is an immunosensor device to enable detection of BW agent specific antigens or extracellular products and toxins, using "capture" and "detection" antibodies, at picogram or sub-picogram levels, from biological fluids. OpTest also is capable of detecting BW agent specific nucleic acids which are liquid hybridized with probes from biologic fluids. OpTest embodies a multi-technology approach to the problem of streamlining and simplifying the currently rigorous requirements of personnel and environment for such testing, while at the same time improving the speed and accuracy of the results obtained. Based upon advanced capabilities in thin film and surface immobilization science , and utilizing a sophisticated but simple optical detection strategy, the OpTest system uses the advantages inherent in a mass-change based approach to immunoaffinity binding reporting, to allow for a testing method that is extremely sensitive, rapid, and which can be produced easily and inexpensively.