Simple and inexpensive yet sensitive and robust diagnostic tests are critically needed for resource-poor settings to enable timely diagnosis and effective use of limited health care resources. Current tests are often too expensive, too slow, or have compromised clinical performance, and they often require health care professional to perform the test. In addition, most assays are not intended to be used in extreme environmental conditions, but their performance may be affected by high temperatures and humidity often encountered in resource-poor settings. This review provides an overview of current immunoassay technologies and their advantages and limitations with respect to their feasibility to resource-poor settings. Future trends of immunoassay development for decentralized testing are also discussed. Homogeneous assays as such are out of the scope of this article because they are generally not yet sensitive enough or otherwise less feasible for inexpensive rapid diagnostic tests. © 2011 Springer-Verlag.