METHODS AND SYSTEMS RELATING TO HIGH SENSITIVITY DIGITAL ASSAYS WITH IMPROVED

Methods and systems are described for captured object-based assays, including metrics for determining the concentration of analyte molecules or particles in a fluid sample. The methods and systems may involve high sensitivity detection of analytes, sometimes using assay conditions and sample manipulation that result in the capture and detection of a high percentage of analyte molecules or particles in a fluid sample using relatively few capture objects. Devices and methods for securing a captured object relative to an assay site, which in some cases have unexpected high efficiency, are also described. Some such devices involve the use of force fields and fluid meniscus forces alone or in combination to facilitate or improve the fixation of captured objects. Also described are techniques for utilizing a relatively high percentage of captured objects in assaying a sample, such as by using the disclosed sample washing techniques, imaging systems, and analytical programs that can reduce the loss of captured objec