This chapter provides a comprehensive review of miniaturized immunoassays. The economic considerations and user needs are discussed. There is a comprehensive analysis of the fundamentals of miniaturization, explaining how the relative effects of forces like surface tension and gravity change as devices and fluidics are reduced in size. These effects can be harnessed to manage flow and other kinetic elements, using forces such as capillary flow. Other means of fluid actuation and movement are described. There is a review of the types of device available, including a systematic look at the key elements of an immunoassay: antibodies, capture/solid phase, calibration, and signal generation and detection, which are covered in further detail. Methods used for microfluidic flow control are described. Analytes for which microfluidic devices have been reported are listed. There is a comprehensive list of commercial microfluidic immunodiagnostic systems, with sources of further information. The final part of the chapter covers microarrays and the detection methods associated with them. This part includes tables of label-free detection methods and commercial microarray systems, The outlook for microarrays in clinical diagnosis is considered.

Simon Rattle is currently an independent consultant to companies in the point-of-care diagnostics arena, providing technical guidance and assistance, particularly in areas of project management where the effectiveness of coordinating the activities of multiple external contractors has a significant impact on the success of development projects. Previously, he spent four years as Chief Technology Officer at Molecular Vision Ltd, leading a group in the development of microfluidic based optical detection systems aimed at point-of-care applications. Prior to that he spent nine years as Technical Director at Genosis plc, a UK based company that successfully developed OTC male and female fertility tests for motile sperm and ovarian reserve. Simon also has many years experience at senior management / director level in the development, manufacture and commercialisation of automated immunoassay systems at Serono Diagnostics Ltd and Anagen plc. He holds a BSc and PhD in chemistry from the University of Birmingham, UK.

Oliver Hofmann is a medical diagnostics expert with more than 10 years industrial experience including positions at Ciba-Geigy (now Novartis) and Vysis Inc. (now part of Abbott). He has been with Molecular Vision Ltd, an optical detection company focused on point-of-care applications, since its inception covering a variety of technical and more recently operational and business development roles. In March 2012. Abingdon Health Ltd, a specialist medical diagnostics commercialization company, acquired a controlling stake in Molecular Vision. Oliver is now conducting business development at Abingdon Health group level, covering Molecular Vision and fellow portfolio companies. He holds a PhD in chemistry from Imperial College and a MBA from Imperial College Business School with a distinction thesis on the commercialization of disruptive technologies in medical diagnostics.

Christopher Price Ph.D., FRCPath, FRSC, FACB, is Visiting Professor in Clinical Biochemistry in the Department of Primary Care Health Sciences, at the University of Oxford. He is also a member of a Monitoring and Diagnosis in Oxford team, funded by the National Institute for Health Research. He was previously Professor of Clinical Biochemistry at the St Bartholomews and Royal London School of Medicine and Dentistry, and Director of Pathology at Barts and the London NHS Trust. While his main career has been in laboratory medicine, including the development of a wide range of immunoassays, his current research interests are mainly in the areas of point-of-care testing and disruptive innovation, evidence-based laboratory medicine, and the challenges of innovation in healthcare.

This chapter also contains material by Larry Kricka and David Wild from the third edition of The Immunoassay Handbook.

Lab-on-a-chip, microarray, microchip, microfluidics, beads, Luminex, xMAP, nanotechnology, nanoparticles, point-of-care, micro total analysis system, bioelectronics, viscosity, surface tension, wetting, capillary flow, diffusion, electroosmotic flow, flow control, competitive, immunometric, ambient analyte, heterogeneous immunoassay, homogeneous immunoassay, electrokinetic, disposability, cartridge, reader, antibodies, solid phase, standardization, calibration, signal generation, signal detection, chemiluminescence, enzymeimmunoassay, fluorescence, supercritical angle fluorescence, phosphorescence, quantum dots, up-converting phosphors, thermal lens microscopy, surface-enhanced Raman scattering, surface plasmon resonance, light-addressable potentiometric sensors, microfluidic paper-based electrochemical devices, field-effect transistors, proteomics, forward-phase protein microarray, reverse-phase protein microarray, matrix-assisted laser-desorption/ionization time-of-flight mass spectroscopy.