Disclosed herein is a method of detecting and identifying antigens that are shed into human bodily fluids during infection. The disclosed method allows circulating antigens associated with a particular infection to be detected within minutes or hours from testing as compared to days required with the current methods. Methods of identifying diagnostic indicators/targets for a given condition or disease are disclosed which include immunizing a veterinary subject with biological fluids obtained from a human infected with particular antigens to identify diagnostic targets for immunoassay. Also disclosed are methods of diagnosing and monitoring a B. pseudomallei-associated condition, such as melioidosis. Point-of-care immunoassays are also provided that can be used to diagnose or monitor the efficacy of a B. pseudomallei-associated condition treatment. These immunoassays can also be used for rapid diagnosis of infection produced by B. pseudomallei, such as meliodosis.