Rapid detection/diagnostic tests are mainly available in two formats: lateral flow immunoassays (strip tests) and enzyme immunoassays (ELISA in microplate or tube format). Both are based on the use of antibodies allowing a recognition of the target with a high specificity. Strip tests have many advantages such as ease of use, robustness, low cost, and speed (maximum response 30'). However, their main limitations (lack of sensitivity, and not quantitative) have not yet been overcome. ELISA tests are very complementary to strip tests, as their sensitivity is better (at least a factor of 10), and allow the quantification of the target. However, unlike lateral flow immunoassays, they require a higher level of technical expertise and a longer time to perform and report results (a few hours). Our objectives are therefore to develop versatile ELISA tests that are as easy as possible, combining the advantages of the strip with those of the ELISA: easily achievable in mobile laboratories, with a higher sensitivity than the strip, in a relatively short time, simple to use, robust, capable of providing a qualitative (presence/absence of the target by eye reading) or quantitative (objective measurement with a spectrophotometer, compared to a standard range) response. The format of the test developed is a sandwich immunoassay which uses magnetic beads functionalized with a monoclonal antibody for the capture of the antigen, and a biotinylated antibody as tracer. Test conditions, such as incubation time, concentration of biological reagents, and number of washes, have been optimized. To date, the field ELISA tests, performed in 1h30, are able to reach a detection limit of 10 pg/ml for ricin and 5.104 cfu/ml for Francisella tularensis.